C++ FF_ARRAY_ELEMS函数代码示例

void ff_h263_encode_picture_header(MpegEncContext * s, int picture_number)
{
    int format, coded_frame_rate, coded_frame_rate_base, i, temp_ref;
    int best_clock_code=1;
    int best_divisor=60;
    int best_error= INT_MAX;

    if(s->h263_plus){
        for(i=0; i<2; i++){
            int div, error;
            div= (s->avctx->time_base.num*1800000LL + 500LL*s->avctx->time_base.den) / ((1000LL+i)*s->avctx->time_base.den);
            div= av_clip(div, 1, 127);
            error= FFABS(s->avctx->time_base.num*1800000LL - (1000LL+i)*s->avctx->time_base.den*div);
            if(error < best_error){
                best_error= error;
                best_divisor= div;
                best_clock_code= i;
            }
        }
    }
    s->custom_pcf= best_clock_code!=1 || best_divisor!=60;
    coded_frame_rate= 1800000;
    coded_frame_rate_base= (1000+best_clock_code)*best_divisor;

    avpriv_align_put_bits(&s->pb);

    /* Update the pointer to last GOB */
    s->ptr_lastgob = put_bits_ptr(&s->pb);
    put_bits(&s->pb, 22, 0x20); /* PSC */
    temp_ref= s->picture_number * (int64_t)coded_frame_rate * s->avctx->time_base.num / //FIXME use timestamp
                         (coded_frame_rate_base * (int64_t)s->avctx->time_base.den);
    put_sbits(&s->pb, 8, temp_ref); /* TemporalReference */

    put_bits(&s->pb, 1, 1);     /* marker */
    put_bits(&s->pb, 1, 0);     /* h263 id */
    put_bits(&s->pb, 1, 0);     /* split screen off */
    put_bits(&s->pb, 1, 0);     /* camera  off */
    put_bits(&s->pb, 1, 0);     /* freeze picture release off */

    format = ff_match_2uint16(ff_h263_format, FF_ARRAY_ELEMS(ff_h263_format), s->width, s->height);
    if (!s->h263_plus) {
        /* H.263v1 */
        put_bits(&s->pb, 3, format);
        put_bits(&s->pb, 1, (s->pict_type == AV_PICTURE_TYPE_P));
        /* By now UMV IS DISABLED ON H.263v1, since the restrictions
        of H.263v1 UMV implies to check the predicted MV after
        calculation of the current MB to see if we're on the limits */
        put_bits(&s->pb, 1, 0);         /* Unrestricted Motion Vector: off */
        put_bits(&s->pb, 1, 0);         /* SAC: off */
        put_bits(&s->pb, 1, s->obmc);   /* Advanced Prediction */
        put_bits(&s->pb, 1, 0);         /* only I/P frames, no PB frame */
        put_bits(&s->pb, 5, s->qscale);
        put_bits(&s->pb, 1, 0);         /* Continuous Presence Multipoint mode: off */
    } else {
        int ufep=1;
        /* H.263v2 */
        /* H.263 Plus PTYPE */

        put_bits(&s->pb, 3, 7);
        put_bits(&s->pb,3,ufep); /* Update Full Extended PTYPE */
        if (format == 8)
            put_bits(&s->pb,3,6); /* Custom Source Format */
        else
            put_bits(&s->pb, 3, format);

        put_bits(&s->pb,1, s->custom_pcf);
        put_bits(&s->pb,1, s->umvplus); /* Unrestricted Motion Vector */
        put_bits(&s->pb,1,0); /* SAC: off */
        put_bits(&s->pb,1,s->obmc); /* Advanced Prediction Mode */
        put_bits(&s->pb,1,s->h263_aic); /* Advanced Intra Coding */
        put_bits(&s->pb,1,s->loop_filter); /* Deblocking Filter */
        put_bits(&s->pb,1,s->h263_slice_structured); /* Slice Structured */
        put_bits(&s->pb,1,0); /* Reference Picture Selection: off */
        put_bits(&s->pb,1,0); /* Independent Segment Decoding: off */
        put_bits(&s->pb,1,s->alt_inter_vlc); /* Alternative Inter VLC */
        put_bits(&s->pb,1,s->modified_quant); /* Modified Quantization: */
        put_bits(&s->pb,1,1); /* "1" to prevent start code emulation */
        put_bits(&s->pb,3,0); /* Reserved */

        put_bits(&s->pb, 3, s->pict_type == AV_PICTURE_TYPE_P);

        put_bits(&s->pb,1,0); /* Reference Picture Resampling: off */
        put_bits(&s->pb,1,0); /* Reduced-Resolution Update: off */
        put_bits(&s->pb,1,s->no_rounding); /* Rounding Type */
        put_bits(&s->pb,2,0); /* Reserved */
        put_bits(&s->pb,1,1); /* "1" to prevent start code emulation */

        /* This should be here if PLUSPTYPE */
        put_bits(&s->pb, 1, 0); /* Continuous Presence Multipoint mode: off */

        if (format == 8) {
            /* Custom Picture Format (CPFMT) */
            s->aspect_ratio_info= ff_h263_aspect_to_info(s->avctx->sample_aspect_ratio);

            put_bits(&s->pb,4,s->aspect_ratio_info);
            put_bits(&s->pb,9,(s->width >> 2) - 1);
            put_bits(&s->pb,1,1); /* "1" to prevent start code emulation */
            put_bits(&s->pb,9,(s->height >> 2));
            if (s->aspect_ratio_info == FF_ASPECT_EXTENDED){
                put_bits(&s->pb, 8, s->avctx->sample_aspect_ratio.num);
//.........这里部分代码省略.........

//.........这里部分代码省略.........
            case 1: {
                const unsigned int abs_diff_pic_num = val + 1;
                int frame_num;

                if (abs_diff_pic_num > sl->max_pic_num) {
                    av_log(h->avctx, AV_LOG_ERROR,
                           "abs_diff_pic_num overflow\n");
                    return AVERROR_INVALIDDATA;
                }

                if (modification_of_pic_nums_idc == 0)
                    pred -= abs_diff_pic_num;
                else
                    pred += abs_diff_pic_num;
                pred &= sl->max_pic_num - 1;

                frame_num = pic_num_extract(h, pred, &pic_structure);

                for (i = h->short_ref_count - 1; i >= 0; i--) {
                    ref = h->short_ref[i];
                    assert(ref->reference);
                    assert(!ref->long_ref);
                    if (ref->frame_num == frame_num &&
                        (ref->reference & pic_structure))
                        break;
                }
                if (i >= 0)
                    ref->pic_id = pred;
                break;
            }
            case 2: {
                int long_idx;
                pic_id = val; // long_term_pic_idx

                long_idx = pic_num_extract(h, pic_id, &pic_structure);

                if (long_idx > 31U) {
                    av_log(h->avctx, AV_LOG_ERROR,
                           "long_term_pic_idx overflow\n");
                    return AVERROR_INVALIDDATA;
                }
                ref = h->long_ref[long_idx];
                assert(!(ref && !ref->reference));
                if (ref && (ref->reference & pic_structure)) {
                    ref->pic_id = pic_id;
                    assert(ref->long_ref);
                    i = 0;
                } else {
                    i = -1;
                }
                break;
            }
            default:
                av_assert0(0);
            }

            if (i < 0) {
                av_log(h->avctx, AV_LOG_ERROR,
                       "reference picture missing during reorder\n");
                memset(&sl->ref_list[list][index], 0, sizeof(sl->ref_list[0][0])); // FIXME
            } else {
                for (i = index; i + 1 < sl->ref_count[list]; i++) {
                    if (sl->ref_list[list][i].parent &&
                        ref->long_ref == sl->ref_list[list][i].parent->long_ref &&
                        ref->pic_id   == sl->ref_list[list][i].pic_id)
                        break;
                }
                for (; i > index; i--) {
                    sl->ref_list[list][i] = sl->ref_list[list][i - 1];
                }
                ref_from_h264pic(&sl->ref_list[list][index], ref);
                if (FIELD_PICTURE(h)) {
                    pic_as_field(&sl->ref_list[list][index], pic_structure);
                }
            }
        }
    }
    for (list = 0; list < sl->list_count; list++) {
        for (index = 0; index < sl->ref_count[list]; index++) {
            if (   !sl->ref_list[list][index].parent
                || (!FIELD_PICTURE(h) && (sl->ref_list[list][index].reference&3) != 3)) {
                int i;
                av_log(h->avctx, AV_LOG_ERROR, "Missing reference picture, default is %d\n", h->default_ref[list].poc);
                for (i = 0; i < FF_ARRAY_ELEMS(h->last_pocs); i++)
                    h->last_pocs[i] = INT_MIN;
                if (h->default_ref[list].parent
                    && !(!FIELD_PICTURE(h) && (h->default_ref[list].reference&3) != 3))
                    sl->ref_list[list][index] = h->default_ref[list];
                else
                    return -1;
            }
            av_assert0(av_buffer_get_ref_count(sl->ref_list[list][index].parent->f->buf[0]) > 0);
        }
    }

    if (FRAME_MBAFF(h))
        h264_fill_mbaff_ref_list(sl);

    return 0;
}

int av_frame_ref(AVFrame *dst, const AVFrame *src)
{
    int i, ret = 0;

    dst->format         = src->format;
    dst->width          = src->width;
    dst->height         = src->height;
    dst->channels       = src->channels;
    dst->channel_layout = src->channel_layout;
    dst->nb_samples     = src->nb_samples;

    ret = frame_copy_props(dst, src, 0);
    if (ret < 0)
        return ret;

    /* duplicate the frame data if it's not refcounted */
    if (!src->buf[0]) {
        ret = av_frame_get_buffer(dst, 32);
        if (ret < 0)
            return ret;

        ret = av_frame_copy(dst, src);
        if (ret < 0)
            av_frame_unref(dst);

        return ret;
    }

    /* ref the buffers */
    for (i = 0; i < FF_ARRAY_ELEMS(src->buf); i++) {
        if (!src->buf[i])
            continue;
        dst->buf[i] = av_buffer_ref(src->buf[i]);
        if (!dst->buf[i]) {
            ret = AVERROR(ENOMEM);
            goto fail;
        }
    }

    if (src->extended_buf) {
        dst->extended_buf = av_mallocz_array(sizeof(*dst->extended_buf),
                                       src->nb_extended_buf);
        if (!dst->extended_buf) {
            ret = AVERROR(ENOMEM);
            goto fail;
        }
        dst->nb_extended_buf = src->nb_extended_buf;

        for (i = 0; i < src->nb_extended_buf; i++) {
            dst->extended_buf[i] = av_buffer_ref(src->extended_buf[i]);
            if (!dst->extended_buf[i]) {
                ret = AVERROR(ENOMEM);
                goto fail;
            }
        }
    }

    /* duplicate extended data */
    if (src->extended_data != src->data) {
        int ch = src->channels;

        if (!ch) {
            ret = AVERROR(EINVAL);
            goto fail;
        }
        CHECK_CHANNELS_CONSISTENCY(src);

        dst->extended_data = av_malloc_array(sizeof(*dst->extended_data), ch);
        if (!dst->extended_data) {
            ret = AVERROR(ENOMEM);
            goto fail;
        }
        memcpy(dst->extended_data, src->extended_data, sizeof(*src->extended_data) * ch);
    } else
        dst->extended_data = dst->data;

    memcpy(dst->data,     src->data,     sizeof(src->data));
    memcpy(dst->linesize, src->linesize, sizeof(src->linesize));

    return 0;

fail:
    av_frame_unref(dst);
    return ret;
}

//.........这里部分代码省略.........
                avio_wl16(pb, n + 1);
                avio_wl16(pb, 26); // name_len
                avio_wl16(pb,  3); // value_type
                avio_wl32(pb,  4); // value_len
                avio_put_str16le(pb, "AspectRatioX");
                avio_wl32(pb, sar.num);
                avio_wl16(pb, 0);
                // the stream number is set like this below
                avio_wl16(pb, n + 1);
                avio_wl16(pb, 26); // name_len
                avio_wl16(pb,  3); // value_type
                avio_wl32(pb,  4); // value_len
                avio_put_str16le(pb, "AspectRatioY");
                avio_wl32(pb, sar.den);
            }
        }
        end_header(pb, hpos2);
    } else {
        avio_wl32(pb, 0);
    }
    end_header(pb, hpos);

    /* title and other infos */
    if (has_title) {
        int len;
        uint8_t *buf;
        AVIOContext *dyn_buf;

        if (avio_open_dyn_buf(&dyn_buf) < 0)
            return AVERROR(ENOMEM);

        hpos = put_header(pb, &ff_asf_comment_header);

        for (n = 0; n < FF_ARRAY_ELEMS(tags); n++) {
            len = tags[n] ? avio_put_str16le(dyn_buf, tags[n]->value) : 0;
            avio_wl16(pb, len);
        }
        len = avio_close_dyn_buf(dyn_buf, &buf);
        avio_write(pb, buf, len);
        av_freep(&buf);
        end_header(pb, hpos);
    }
    if (metadata_count) {
        AVDictionaryEntry *tag = NULL;
        hpos = put_header(pb, &ff_asf_extended_content_header);
        avio_wl16(pb, metadata_count);
        while ((tag = av_dict_get(s->metadata, "", tag, AV_DICT_IGNORE_SUFFIX))) {
            put_str16(pb, tag->key);
            avio_wl16(pb, 0);
            put_str16(pb, tag->value);
        }
        end_header(pb, hpos);
    }
    /* chapters using ASF markers */
    if (!asf->is_streamed && s->nb_chapters) {
        int ret;
        if (ret = asf_write_markers(s))
            return ret;
    }
    /* stream headers */
    for (n = 0; n < s->nb_streams; n++) {
        int64_t es_pos;
        //        ASFStream *stream = &asf->streams[n];

        enc                 = s->streams[n]->codec;
        asf->streams[n].num = n + 1;

/* add a codec and set the default parameters */
static void add_codec(FFServerStream *stream, AVCodecContext *av,
                      FFServerConfig *config)
{
    AVStream *st;
    AVDictionary **opts, *recommended = NULL;
    char *enc_config;

    if(stream->nb_streams >= FF_ARRAY_ELEMS(stream->streams))
        return;

    opts = av->codec_type == AVMEDIA_TYPE_AUDIO ?
           &config->audio_opts : &config->video_opts;
    av_dict_copy(&recommended, *opts, 0);
    av_opt_set_dict2(av->priv_data, opts, AV_OPT_SEARCH_CHILDREN);
    av_opt_set_dict2(av, opts, AV_OPT_SEARCH_CHILDREN);

    if (av_dict_count(*opts))
        av_log(NULL, AV_LOG_WARNING,
               "Something is wrong, %d options are not set!\n",
               av_dict_count(*opts));

    if (!config->stream_use_defaults) {
        switch(av->codec_type) {
        case AVMEDIA_TYPE_AUDIO:
            if (av->bit_rate == 0)
                report_config_error(config->filename, config->line_num,
                                    AV_LOG_ERROR, &config->errors,
                                    "audio bit rate is not set\n");
            if (av->sample_rate == 0)
                report_config_error(config->filename, config->line_num,
                                    AV_LOG_ERROR, &config->errors,
                                    "audio sample rate is not set\n");
            break;
        case AVMEDIA_TYPE_VIDEO:
            if (av->width == 0 || av->height == 0)
                report_config_error(config->filename, config->line_num,
                                    AV_LOG_ERROR, &config->errors,
                                    "video size is not set\n");
            break;
        default:
            av_assert0(0);
        }
        goto done;
    }

    /* stream_use_defaults = true */

    /* compute default parameters */
    switch(av->codec_type) {
    case AVMEDIA_TYPE_AUDIO:
        if (!av_dict_get(recommended, "b", NULL, 0)) {
            av->bit_rate = 64000;
            av_dict_set_int(&recommended, "b", av->bit_rate, 0);
            WARNING("Setting default value for audio bit rate = %d. "
                    "Use NoDefaults to disable it.\n",
                    av->bit_rate);
        }
        if (!av_dict_get(recommended, "ar", NULL, 0)) {
            av->sample_rate = 22050;
            av_dict_set_int(&recommended, "ar", av->sample_rate, 0);
            WARNING("Setting default value for audio sample rate = %d. "
                    "Use NoDefaults to disable it.\n",
                    av->sample_rate);
        }
        if (!av_dict_get(recommended, "ac", NULL, 0)) {
            av->channels = 1;
            av_dict_set_int(&recommended, "ac", av->channels, 0);
            WARNING("Setting default value for audio channel count = %d. "
                    "Use NoDefaults to disable it.\n",
                    av->channels);
        }
        break;
    case AVMEDIA_TYPE_VIDEO:
        if (!av_dict_get(recommended, "b", NULL, 0)) {
            av->bit_rate = 64000;
            av_dict_set_int(&recommended, "b", av->bit_rate, 0);
            WARNING("Setting default value for video bit rate = %d. "
                    "Use NoDefaults to disable it.\n",
                    av->bit_rate);
        }
        if (!av_dict_get(recommended, "time_base", NULL, 0)) {
            av->time_base.den = 5;
            av->time_base.num = 1;
            av_dict_set(&recommended, "time_base", "1/5", 0);
            WARNING("Setting default value for video frame rate = %d. "
                    "Use NoDefaults to disable it.\n",
                    av->time_base.den);
        }
        if (!av_dict_get(recommended, "video_size", NULL, 0)) {
            av->width = 160;
            av->height = 128;
            av_dict_set(&recommended, "video_size", "160x128", 0);
            WARNING("Setting default value for video size = %dx%d. "
                    "Use NoDefaults to disable it.\n",
                    av->width, av->height);
        }
        /* Bitrate tolerance is less for streaming */
        if (!av_dict_get(recommended, "bt", NULL, 0)) {
            av->bit_rate_tolerance = FFMAX(av->bit_rate / 4,
//.........这里部分代码省略.........

static void swap_channel_layouts_on_filter(AVFilterContext *filter)
{
    AVFilterLink *link = NULL;
    int i, j, k;

    for (i = 0; i < filter->nb_inputs; i++) {
        link = filter->inputs[i];

        if (link->type == AVMEDIA_TYPE_AUDIO &&
            link->out_channel_layouts->nb_channel_layouts == 1)
            break;
    }
    if (i == filter->nb_inputs)
        return;

    for (i = 0; i < filter->nb_outputs; i++) {
        AVFilterLink *outlink = filter->outputs[i];
        int best_idx = -1, best_score = INT_MIN, best_count_diff = INT_MAX;

        if (outlink->type != AVMEDIA_TYPE_AUDIO ||
            outlink->in_channel_layouts->nb_channel_layouts < 2)
            continue;

        for (j = 0; j < outlink->in_channel_layouts->nb_channel_layouts; j++) {
            uint64_t  in_chlayout = link->out_channel_layouts->channel_layouts[0];
            uint64_t out_chlayout = outlink->in_channel_layouts->channel_layouts[j];
            int  in_channels      = av_get_channel_layout_nb_channels(in_chlayout);
            int out_channels      = av_get_channel_layout_nb_channels(out_chlayout);
            int count_diff        = out_channels - in_channels;
            int matched_channels, extra_channels;
            int score = 100000;

            if (FF_LAYOUT2COUNT(in_chlayout) || FF_LAYOUT2COUNT(out_chlayout)) {
                /* Compute score in case the input or output layout encodes
                   a channel count; in this case the score is not altered by
                   the computation afterwards, as in_chlayout and
                   out_chlayout have both been set to 0 */
                if (FF_LAYOUT2COUNT(in_chlayout))
                    in_channels = FF_LAYOUT2COUNT(in_chlayout);
                if (FF_LAYOUT2COUNT(out_chlayout))
                    out_channels = FF_LAYOUT2COUNT(out_chlayout);
                score -= 10000 + FFABS(out_channels - in_channels) +
                         (in_channels > out_channels ? 10000 : 0);
                in_chlayout = out_chlayout = 0;
                /* Let the remaining computation run, even if the score
                   value is not altered */
            }

            /* channel substitution */
            for (k = 0; k < FF_ARRAY_ELEMS(ch_subst); k++) {
                uint64_t cmp0 = ch_subst[k][0];
                uint64_t cmp1 = ch_subst[k][1];
                if (( in_chlayout & cmp0) && (!(out_chlayout & cmp0)) &&
                    (out_chlayout & cmp1) && (!( in_chlayout & cmp1))) {
                    in_chlayout  &= ~cmp0;
                    out_chlayout &= ~cmp1;
                    /* add score for channel match, minus a deduction for
                       having to do the substitution */
                    score += 10 * av_get_channel_layout_nb_channels(cmp1) - 2;
                }
            }

            /* no penalty for LFE channel mismatch */
            if ( (in_chlayout & AV_CH_LOW_FREQUENCY) &&
                (out_chlayout & AV_CH_LOW_FREQUENCY))
                score += 10;
            in_chlayout  &= ~AV_CH_LOW_FREQUENCY;
            out_chlayout &= ~AV_CH_LOW_FREQUENCY;

            matched_channels = av_get_channel_layout_nb_channels(in_chlayout &
                                                                 out_chlayout);
            extra_channels   = av_get_channel_layout_nb_channels(out_chlayout &
                                                                 (~in_chlayout));
            score += 10 * matched_channels - 5 * extra_channels;

            if (score > best_score ||
                (count_diff < best_count_diff && score == best_score)) {
                best_score = score;
                best_idx   = j;
                best_count_diff = count_diff;
            }
        }
        av_assert0(best_idx >= 0);
        FFSWAP(uint64_t, outlink->in_channel_layouts->channel_layouts[0],
               outlink->in_channel_layouts->channel_layouts[best_idx]);
    }

}

static int cuda_transfer_data_from(AVHWFramesContext *ctx, AVFrame *dst,
                                   const AVFrame *src)
{
    CUDAFramesContext           *priv = ctx->internal->priv;
    AVCUDADeviceContext *device_hwctx = ctx->device_ctx->hwctx;
    CudaFunctions                 *cu = device_hwctx->internal->cuda_dl;

    CUcontext dummy;
    CUresult err;
    int i;

    err = cu->cuCtxPushCurrent(device_hwctx->cuda_ctx);
    if (err != CUDA_SUCCESS)
        return AVERROR_UNKNOWN;

    for (i = 0; i < FF_ARRAY_ELEMS(src->data) && src->data[i]; i++) {
        CUDA_MEMCPY2D cpy = {
            .srcMemoryType = CU_MEMORYTYPE_DEVICE,
            .dstMemoryType = CU_MEMORYTYPE_HOST,
            .srcDevice     = (CUdeviceptr)src->data[i],
            .dstHost       = dst->data[i],
            .srcPitch      = src->linesize[i],
            .dstPitch      = dst->linesize[i],
            .WidthInBytes  = FFMIN(src->linesize[i], dst->linesize[i]),
            .Height        = src->height >> (i ? priv->shift_height : 0),
        };

        err = cu->cuMemcpy2D(&cpy);
        if (err != CUDA_SUCCESS) {
            av_log(ctx, AV_LOG_ERROR, "Error transferring the data from the CUDA frame\n");
            return AVERROR_UNKNOWN;
        }
    }

    cu->cuCtxPopCurrent(&dummy);

    return 0;
}

static int cuda_transfer_data_to(AVHWFramesContext *ctx, AVFrame *dst,
                                 const AVFrame *src)
{
    CUDAFramesContext           *priv = ctx->internal->priv;
    AVCUDADeviceContext *device_hwctx = ctx->device_ctx->hwctx;
    CudaFunctions                 *cu = device_hwctx->internal->cuda_dl;

    CUcontext dummy;
    CUresult err;
    int i;

    err = cu->cuCtxPushCurrent(device_hwctx->cuda_ctx);
    if (err != CUDA_SUCCESS)
        return AVERROR_UNKNOWN;

    for (i = 0; i < FF_ARRAY_ELEMS(src->data) && src->data[i]; i++) {
        CUDA_MEMCPY2D cpy = {
            .srcMemoryType = CU_MEMORYTYPE_HOST,
            .dstMemoryType = CU_MEMORYTYPE_DEVICE,
            .srcHost       = src->data[i],
            .dstDevice     = (CUdeviceptr)dst->data[i],
            .srcPitch      = src->linesize[i],
            .dstPitch      = dst->linesize[i],
            .WidthInBytes  = FFMIN(src->linesize[i], dst->linesize[i]),
            .Height        = src->height >> (i ? priv->shift_height : 0),
        };

        err = cu->cuMemcpy2D(&cpy);
        if (err != CUDA_SUCCESS) {
            av_log(ctx, AV_LOG_ERROR, "Error transferring the data from the CUDA frame\n");
            return AVERROR_UNKNOWN;
        }
    }

    cu->cuCtxPopCurrent(&dummy);

    return 0;
}

static void cuda_device_uninit(AVHWDeviceContext *ctx)
{
    AVCUDADeviceContext *hwctx = ctx->hwctx;

    if (hwctx->internal) {
        if (hwctx->internal->is_allocated && hwctx->cuda_ctx) {
            hwctx->internal->cuda_dl->cuCtxDestroy(hwctx->cuda_ctx);
            hwctx->cuda_ctx = NULL;
        }
        cuda_free_functions(&hwctx->internal->cuda_dl);
    }

    av_freep(&hwctx->internal);
}

static int opus_decode_packet(AVCodecContext *avctx, void *data,
                              int *got_frame_ptr, AVPacket *avpkt)
{
    OpusContext *c      = avctx->priv_data;
    AVFrame *frame      = data;
    const uint8_t *buf  = avpkt->data;
    int buf_size        = avpkt->size;
    int coded_samples   = 0;
    int decoded_samples = INT_MAX;
    int delayed_samples = 0;
    int i, ret;

    /* calculate the number of delayed samples */
    for (i = 0; i < c->nb_streams; i++) {
        OpusStreamContext *s = &c->streams[i];
        s->out[0] =
        s->out[1] = NULL;
        delayed_samples = FFMAX(delayed_samples,
                                s->delayed_samples + av_audio_fifo_size(c->sync_buffers[i]));
    }

    /* decode the header of the first sub-packet to find out the sample count */
    if (buf) {
        OpusPacket *pkt = &c->streams[0].packet;
        ret = ff_opus_parse_packet(pkt, buf, buf_size, c->nb_streams > 1);
        if (ret < 0) {
            av_log(avctx, AV_LOG_ERROR, "Error parsing the packet header.\n");
            return ret;
        }
        coded_samples += pkt->frame_count * pkt->frame_duration;
        c->streams[0].silk_samplerate = get_silk_samplerate(pkt->config);
    }

    frame->nb_samples = coded_samples + delayed_samples;

    /* no input or buffered data => nothing to do */
    if (!frame->nb_samples) {
        *got_frame_ptr = 0;
        return 0;
    }

    /* setup the data buffers */
    ret = ff_get_buffer(avctx, frame, 0);
    if (ret < 0)
        return ret;
    frame->nb_samples = 0;

    memset(c->out, 0, c->nb_streams * 2 * sizeof(*c->out));
    for (i = 0; i < avctx->channels; i++) {
        ChannelMap *map = &c->channel_maps[i];
        if (!map->copy)
            c->out[2 * map->stream_idx + map->channel_idx] = (float*)frame->extended_data[i];
    }

    /* read the data from the sync buffers */
    for (i = 0; i < c->nb_streams; i++) {
        float          **out = c->out + 2 * i;
        int sync_size = av_audio_fifo_size(c->sync_buffers[i]);

        float sync_dummy[32];
        int out_dummy = (!out[0]) | ((!out[1]) << 1);

        if (!out[0])
            out[0] = sync_dummy;
        if (!out[1])
            out[1] = sync_dummy;
        if (out_dummy && sync_size > FF_ARRAY_ELEMS(sync_dummy))
            return AVERROR_BUG;

        ret = av_audio_fifo_read(c->sync_buffers[i], (void**)out, sync_size);
        if (ret < 0)
            return ret;

        if (out_dummy & 1)
            out[0] = NULL;
        else
            out[0] += ret;
        if (out_dummy & 2)
            out[1] = NULL;
        else
            out[1] += ret;

        c->out_size[i] = frame->linesize[0] - ret * sizeof(float);
    }

    /* decode each sub-packet */
    for (i = 0; i < c->nb_streams; i++) {
        OpusStreamContext *s = &c->streams[i];

        if (i && buf) {
            ret = ff_opus_parse_packet(&s->packet, buf, buf_size, i != c->nb_streams - 1);
            if (ret < 0) {
                av_log(avctx, AV_LOG_ERROR, "Error parsing the packet header.\n");
                return ret;
            }
            if (coded_samples != s->packet.frame_count * s->packet.frame_duration) {
                av_log(avctx, AV_LOG_ERROR,
                       "Mismatching coded sample count in substream %d.\n", i);
                return AVERROR_INVALIDDATA;
            }
//.........这里部分代码省略.........

static void fill_slice_long(AVCodecContext *avctx, DXVA_Slice_H264_Long *slice,
                            unsigned position, unsigned size)
{
    const H264Context *h = avctx->priv_data;
    struct dxva_context *ctx = avctx->hwaccel_context;
    unsigned list;

    memset(slice, 0, sizeof(*slice));
    slice->BSNALunitDataLocation = position;
    slice->SliceBytesInBuffer    = size;
    slice->wBadSliceChopping     = 0;

    slice->first_mb_in_slice     = (h->mb_y >> FIELD_OR_MBAFF_PICTURE) * h->mb_width + h->mb_x;
    slice->NumMbsForSlice        = 0; /* XXX it is set once we have all slices */
    slice->BitOffsetToSliceData  = get_bits_count(&h->gb);
    slice->slice_type            = ff_h264_get_slice_type(h);
    if (h->slice_type_fixed)
        slice->slice_type += 5;
    slice->luma_log2_weight_denom       = h->luma_log2_weight_denom;
    slice->chroma_log2_weight_denom     = h->chroma_log2_weight_denom;
    if (h->list_count > 0)
        slice->num_ref_idx_l0_active_minus1 = h->ref_count[0] - 1;
    if (h->list_count > 1)
        slice->num_ref_idx_l1_active_minus1 = h->ref_count[1] - 1;
    slice->slice_alpha_c0_offset_div2   = h->slice_alpha_c0_offset / 2 - 26;
    slice->slice_beta_offset_div2       = h->slice_beta_offset     / 2 - 26;
    slice->Reserved8Bits                = 0;

    for (list = 0; list < 2; list++) {
        unsigned i;
        for (i = 0; i < FF_ARRAY_ELEMS(slice->RefPicList[list]); i++) {
            if (list < h->list_count && i < h->ref_count[list]) {
                const Picture *r = &h->ref_list[list][i];
                unsigned plane;
                fill_picture_entry(&slice->RefPicList[list][i],
                                   ff_dxva2_get_surface_index(ctx, r),
                                   r->f.reference == PICT_BOTTOM_FIELD);
                for (plane = 0; plane < 3; plane++) {
                    int w, o;
                    if (plane == 0 && h->luma_weight_flag[list]) {
                        w = h->luma_weight[i][list][0];
                        o = h->luma_weight[i][list][1];
                    } else if (plane >= 1 && h->chroma_weight_flag[list]) {
                        w = h->chroma_weight[i][list][plane-1][0];
                        o = h->chroma_weight[i][list][plane-1][1];
                    } else {
                        w = 1 << (plane == 0 ? h->luma_log2_weight_denom :
                                               h->chroma_log2_weight_denom);
                        o = 0;
                    }
                    slice->Weights[list][i][plane][0] = w;
                    slice->Weights[list][i][plane][1] = o;
                }
            } else {
                unsigned plane;
                slice->RefPicList[list][i].bPicEntry = 0xff;
                for (plane = 0; plane < 3; plane++) {
                    slice->Weights[list][i][plane][0] = 0;
                    slice->Weights[list][i][plane][1] = 0;
                }
            }
        }
    }
    slice->slice_qs_delta    = 0; /* XXX not implemented by Libav */
    slice->slice_qp_delta    = h->qscale - h->pps.init_qp;
    slice->redundant_pic_cnt = h->redundant_pic_count;
    if (h->slice_type == AV_PICTURE_TYPE_B)
        slice->direct_spatial_mv_pred_flag = h->direct_spatial_mv_pred;
    slice->cabac_init_idc = h->pps.cabac ? h->cabac_init_idc : 0;
    if (h->deblocking_filter < 2)
        slice->disable_deblocking_filter_idc = 1 - h->deblocking_filter;
    else
        slice->disable_deblocking_filter_idc = h->deblocking_filter;
    slice->slice_id = h->current_slice - 1;
}

static int vaapi_encode_h264_init_sequence_params(AVCodecContext *avctx)
{
    VAAPIEncodeContext                 *ctx = avctx->priv_data;
    VAEncSequenceParameterBufferH264  *vseq = ctx->codec_sequence_params;
    VAEncPictureParameterBufferH264   *vpic = ctx->codec_picture_params;
    VAAPIEncodeH264Context            *priv = ctx->priv_data;
    VAAPIEncodeH264MiscSequenceParams *mseq = &priv->misc_sequence_params;
    int i;

    {
        vseq->seq_parameter_set_id = 0;

        vseq->level_idc = avctx->level;

        vseq->max_num_ref_frames = 2;

        vseq->picture_width_in_mbs  = priv->mb_width;
        vseq->picture_height_in_mbs = priv->mb_height;

        vseq->seq_fields.bits.chroma_format_idc = 1;
        vseq->seq_fields.bits.frame_mbs_only_flag = 1;
        vseq->seq_fields.bits.direct_8x8_inference_flag = 1;
        vseq->seq_fields.bits.log2_max_frame_num_minus4 = 4;
        vseq->seq_fields.bits.pic_order_cnt_type = 0;

        if (ctx->input_width  != ctx->aligned_width ||
            ctx->input_height != ctx->aligned_height) {
            vseq->frame_cropping_flag = 1;

            vseq->frame_crop_left_offset   = 0;
            vseq->frame_crop_right_offset  =
                (ctx->aligned_width - ctx->input_width) / 2;
            vseq->frame_crop_top_offset    = 0;
            vseq->frame_crop_bottom_offset =
                (ctx->aligned_height - ctx->input_height) / 2;
        } else {
            vseq->frame_cropping_flag = 0;
        }

        vseq->bits_per_second = avctx->bit_rate;
        if (avctx->framerate.num > 0 && avctx->framerate.den > 0) {
            vseq->num_units_in_tick = avctx->framerate.num;
            vseq->time_scale        = 2 * avctx->framerate.den;
        } else {
            vseq->num_units_in_tick = avctx->time_base.num;
            vseq->time_scale        = 2 * avctx->time_base.den;
        }

        vseq->intra_period     = ctx->p_per_i * (ctx->b_per_p + 1);
        vseq->intra_idr_period = vseq->intra_period;
        vseq->ip_period        = ctx->b_per_p + 1;
    }

    {
        vpic->CurrPic.picture_id = VA_INVALID_ID;
        vpic->CurrPic.flags      = VA_PICTURE_H264_INVALID;

        for (i = 0; i < FF_ARRAY_ELEMS(vpic->ReferenceFrames); i++) {
            vpic->ReferenceFrames[i].picture_id = VA_INVALID_ID;
            vpic->ReferenceFrames[i].flags      = VA_PICTURE_H264_INVALID;
        }

        vpic->coded_buf = VA_INVALID_ID;

        vpic->pic_parameter_set_id = 0;
        vpic->seq_parameter_set_id = 0;

        vpic->num_ref_idx_l0_active_minus1 = 0;
        vpic->num_ref_idx_l1_active_minus1 = 0;

        vpic->pic_fields.bits.entropy_coding_mode_flag =
            ((avctx->profile & 0xff) != 66);
        vpic->pic_fields.bits.weighted_pred_flag = 0;
        vpic->pic_fields.bits.weighted_bipred_idc = 0;
        vpic->pic_fields.bits.transform_8x8_mode_flag =
            ((avctx->profile & 0xff) >= 100);

        vpic->pic_init_qp = priv->fixed_qp_idr;
    }

    {
        mseq->profile_idc = avctx->profile & 0xff;

        if (avctx->profile & FF_PROFILE_H264_CONSTRAINED)
            mseq->constraint_set1_flag = 1;
        if (avctx->profile & FF_PROFILE_H264_INTRA)
            mseq->constraint_set3_flag = 1;
    }

    return 0;
}

static int vaapi_encode_h264_init_slice_params(AVCodecContext *avctx,
                                               VAAPIEncodePicture *pic,
                                               VAAPIEncodeSlice *slice)
{
    VAAPIEncodeContext                 *ctx = avctx->priv_data;
    VAEncSequenceParameterBufferH264  *vseq = ctx->codec_sequence_params;
    VAEncPictureParameterBufferH264   *vpic = pic->codec_picture_params;
    VAEncSliceParameterBufferH264   *vslice = slice->codec_slice_params;
    VAAPIEncodeH264Context            *priv = ctx->priv_data;
    VAAPIEncodeH264Slice            *pslice;
    VAAPIEncodeH264MiscSliceParams  *mslice;
    int i;

    slice->priv_data = av_mallocz(sizeof(*pslice));
    if (!slice->priv_data)
        return AVERROR(ENOMEM);
    pslice = slice->priv_data;
    mslice = &pslice->misc_slice_params;

    if (pic->type == PICTURE_TYPE_IDR)
        mslice->nal_unit_type = NAL_IDR_SLICE;
    else
        mslice->nal_unit_type = NAL_SLICE;

    switch (pic->type) {
    case PICTURE_TYPE_IDR:
        vslice->slice_type  = SLICE_TYPE_I;
        mslice->nal_ref_idc = 3;
        break;
    case PICTURE_TYPE_I:
        vslice->slice_type  = SLICE_TYPE_I;
        mslice->nal_ref_idc = 2;
        break;
    case PICTURE_TYPE_P:
        vslice->slice_type  = SLICE_TYPE_P;
        mslice->nal_ref_idc = 1;
        break;
    case PICTURE_TYPE_B:
        vslice->slice_type  = SLICE_TYPE_B;
        mslice->nal_ref_idc = 0;
        break;
    default:
        av_assert0(0 && "invalid picture type");
    }

    // Only one slice per frame.
    vslice->macroblock_address = 0;
    vslice->num_macroblocks = priv->mb_width * priv->mb_height;

    vslice->macroblock_info = VA_INVALID_ID;

    vslice->pic_parameter_set_id = vpic->pic_parameter_set_id;
    vslice->idr_pic_id = priv->idr_pic_count++;

    vslice->pic_order_cnt_lsb = pic->display_order &
        ((1 << (4 + vseq->seq_fields.bits.log2_max_pic_order_cnt_lsb_minus4)) - 1);

    for (i = 0; i < FF_ARRAY_ELEMS(vslice->RefPicList0); i++) {
        vslice->RefPicList0[i].picture_id = VA_INVALID_ID;
        vslice->RefPicList0[i].flags      = VA_PICTURE_H264_INVALID;
        vslice->RefPicList1[i].picture_id = VA_INVALID_ID;
        vslice->RefPicList1[i].flags      = VA_PICTURE_H264_INVALID;
    }

    av_assert0(pic->nb_refs <= 2);
    if (pic->nb_refs >= 1) {
        // Backward reference for P- or B-frame.
        av_assert0(pic->type == PICTURE_TYPE_P ||
                   pic->type == PICTURE_TYPE_B);

        vslice->num_ref_idx_l0_active_minus1 = 0;
        vslice->RefPicList0[0] = vpic->ReferenceFrames[0];
    }
    if (pic->nb_refs >= 2) {
        // Forward reference for B-frame.
        av_assert0(pic->type == PICTURE_TYPE_B);

        vslice->num_ref_idx_l1_active_minus1 = 0;
        vslice->RefPicList1[0] = vpic->ReferenceFrames[1];
    }

    if (pic->type == PICTURE_TYPE_B)
        vslice->slice_qp_delta = priv->fixed_qp_b - vpic->pic_init_qp;
    else if (pic->type == PICTURE_TYPE_P)
        vslice->slice_qp_delta = priv->fixed_qp_p - vpic->pic_init_qp;
    else
        vslice->slice_qp_delta = priv->fixed_qp_idr - vpic->pic_init_qp;

    vslice->direct_spatial_mv_pred_flag = 1;

    return 0;
}

static int dxva2_init_pool(AVHWFramesContext *ctx)
{
    AVDXVA2FramesContext *frames_hwctx = ctx->hwctx;
    AVDXVA2DeviceContext *device_hwctx = ctx->device_ctx->hwctx;
    DXVA2FramesContext              *s = ctx->internal->priv;
    int decode = (frames_hwctx->surface_type == DXVA2_VideoDecoderRenderTarget);

    int i;
    HRESULT hr;

    if (ctx->initial_pool_size <= 0)
        return 0;

    hr = IDirect3DDeviceManager9_OpenDeviceHandle(device_hwctx->devmgr, &s->device_handle);
    if (FAILED(hr)) {
        av_log(ctx, AV_LOG_ERROR, "Failed to open device handle\n");
        return AVERROR_UNKNOWN;
    }

    hr = IDirect3DDeviceManager9_GetVideoService(device_hwctx->devmgr,
                                                 s->device_handle,
                                                 decode ? &video_decoder_service : &video_processor_service,
                                                 (void **)&s->service);
    if (FAILED(hr)) {
        av_log(ctx, AV_LOG_ERROR, "Failed to create the video service\n");
        return AVERROR_UNKNOWN;
    }

    for (i = 0; i < FF_ARRAY_ELEMS(supported_formats); i++) {
        if (ctx->sw_format == supported_formats[i].pix_fmt) {
            s->format = supported_formats[i].d3d_format;
            break;
        }
    }
    if (i == FF_ARRAY_ELEMS(supported_formats)) {
        av_log(ctx, AV_LOG_ERROR, "Unsupported pixel format: %s\n",
               av_get_pix_fmt_name(ctx->sw_format));
        return AVERROR(EINVAL);
    }

    s->surfaces_internal = av_mallocz_array(ctx->initial_pool_size,
                                            sizeof(*s->surfaces_internal));
    if (!s->surfaces_internal)
        return AVERROR(ENOMEM);

    hr = IDirectXVideoAccelerationService_CreateSurface(s->service,
                                                        ctx->width, ctx->height,
                                                        ctx->initial_pool_size - 1,
                                                        s->format, D3DPOOL_DEFAULT, 0,
                                                        frames_hwctx->surface_type,
                                                        s->surfaces_internal, NULL);
    if (FAILED(hr)) {
        av_log(ctx, AV_LOG_ERROR, "Could not create the surfaces\n");
        return AVERROR_UNKNOWN;
    }

    ctx->internal->pool_internal = av_buffer_pool_init2(sizeof(*s->surfaces_internal),
                                                        ctx, dxva2_pool_alloc, NULL);
    if (!ctx->internal->pool_internal)
        return AVERROR(ENOMEM);

    frames_hwctx->surfaces    = s->surfaces_internal;
    frames_hwctx->nb_surfaces = ctx->initial_pool_size;

    return 0;
}

int ff_h264_fill_default_ref_list(H264Context *h)
{
    int i, len;

    if (h->slice_type_nos == AV_PICTURE_TYPE_B) {
        H264Picture *sorted[32];
        int cur_poc, list;
        int lens[2];

        if (FIELD_PICTURE(h))
            cur_poc = h->cur_pic_ptr->field_poc[h->picture_structure == PICT_BOTTOM_FIELD];
        else
            cur_poc = h->cur_pic_ptr->poc;

        for (list = 0; list < 2; list++) {
            len  = add_sorted(sorted,       h->short_ref, h->short_ref_count, cur_poc, 1 ^ list);
            len += add_sorted(sorted + len, h->short_ref, h->short_ref_count, cur_poc, 0 ^ list);
            av_assert0(len <= 32);

            len  = build_def_list(h->default_ref_list[list], FF_ARRAY_ELEMS(h->default_ref_list[0]),
                                  sorted, len, 0, h->picture_structure);
            len += build_def_list(h->default_ref_list[list] + len,
                                  FF_ARRAY_ELEMS(h->default_ref_list[0]) - len,
                                  h->long_ref, 16, 1, h->picture_structure);
            av_assert0(len <= 32);

            if (len < h->ref_count[list])
                memset(&h->default_ref_list[list][len], 0, sizeof(H264Picture) * (h->ref_count[list] - len));
            lens[list] = len;
        }

        if (lens[0] == lens[1] && lens[1] > 1) {
            for (i = 0; i < lens[0] &&
                        h->default_ref_list[0][i].f.buf[0]->buffer ==
                        h->default_ref_list[1][i].f.buf[0]->buffer; i++);
            if (i == lens[0]) {
                H264Picture tmp;
                COPY_PICTURE(&tmp, &h->default_ref_list[1][0]);
                COPY_PICTURE(&h->default_ref_list[1][0], &h->default_ref_list[1][1]);
                COPY_PICTURE(&h->default_ref_list[1][1], &tmp);
            }
        }
    } else {
        len  = build_def_list(h->default_ref_list[0], FF_ARRAY_ELEMS(h->default_ref_list[0]),
                              h->short_ref, h->short_ref_count, 0, h->picture_structure);
        len += build_def_list(h->default_ref_list[0] + len,
                              FF_ARRAY_ELEMS(h->default_ref_list[0]) - len,
                              h-> long_ref, 16, 1, h->picture_structure);
        av_assert0(len <= 32);

        if (len < h->ref_count[0])
            memset(&h->default_ref_list[0][len], 0, sizeof(H264Picture) * (h->ref_count[0] - len));
    }
#ifdef TRACE
    for (i = 0; i < h->ref_count[0]; i++) {
        tprintf(h->avctx, "List0: %s fn:%d 0x%p\n",
                (h->default_ref_list[0][i].long_ref ? "LT" : "ST"),
                h->default_ref_list[0][i].pic_id,
                h->default_ref_list[0][i].f.data[0]);
    }
    if (h->slice_type_nos == AV_PICTURE_TYPE_B) {
        for (i = 0; i < h->ref_count[1]; i++) {
            tprintf(h->avctx, "List1: %s fn:%d 0x%p\n",
                    (h->default_ref_list[1][i].long_ref ? "LT" : "ST"),
                    h->default_ref_list[1][i].pic_id,
                    h->default_ref_list[1][i].f.data[0]);
        }
    }
#endif
    return 0;
}

//.........这里部分代码省略.........
    }
    /* See section 7.4.7.2 of the specification. */
    info->NumPocTotalCurr = ff_hevc_frame_nb_refs(h);
    if (sh->short_term_ref_pic_set_sps_flag == 0 && sh->short_term_rps) {
        /* Corresponds to specification field, NumDeltaPocs[RefRpsIdx].
           Only applicable when short_term_ref_pic_set_sps_flag == 0.
           Implementations will ignore this value in other cases. See 7.4.8. */
        info->NumDeltaPocsOfRefRpsIdx = sh->short_term_rps->rps_idx_num_delta_pocs;
    }
    /* Section 7.6.3.1 of the H.265/HEVC Specification defines the syntax of
       the slice_segment_header. This header contains information that
       some VDPAU implementations may choose to skip. The VDPAU API
       requires client applications to track the number of bits used in the
       slice header for structures associated with short term and long term
       reference pictures. First, VDPAU requires the number of bits used by
       the short_term_ref_pic_set array in the slice_segment_header. */
    info->NumShortTermPictureSliceHeaderBits = sh->short_term_ref_pic_set_size;
    /* Second, VDPAU requires the number of bits used for long term reference
       pictures in the slice_segment_header. This is equal to the number
       of bits used for the contents of the block beginning with
       "if(long_term_ref_pics_present_flag)". */
    info->NumLongTermPictureSliceHeaderBits = sh->long_term_ref_pic_set_size;

    /* The value of PicOrderCntVal of the picture in the access unit
       containing the SEI message. The picture being decoded. */
    info->CurrPicOrderCntVal = h->poc;

    /* Slice Decoding Process - Reference Picture Sets */
    for (size_t i = 0; i < 16; i++) {
        info->RefPics[i] = VDP_INVALID_HANDLE;
        info->PicOrderCntVal[i] = 0;
        info->IsLongTerm[i] = 0;
    }
    for (size_t i = 0, j = 0; i < FF_ARRAY_ELEMS(h->DPB); i++) {
        const HEVCFrame *frame = &h->DPB[i];
        if (frame != h->ref && (frame->flags & (HEVC_FRAME_FLAG_LONG_REF |
                                                HEVC_FRAME_FLAG_SHORT_REF))) {
            if (j > 15) {
                av_log(avctx, AV_LOG_WARNING,
                     "VDPAU only supports up to 16 references in the DPB. "
                     "This frame may not be decoded correctly.\n");
                break;
            }
            /* Array of video reference surfaces.
               Set any unused positions to VDP_INVALID_HANDLE. */
            info->RefPics[j] = ff_vdpau_get_surface_id(frame->frame);
            /* Array of picture order counts. These correspond to positions
               in the RefPics array. */
            info->PicOrderCntVal[j] = frame->poc;
            /* Array used to specify whether a particular RefPic is
               a long term reference. A value of "1" indicates a long-term
               reference. */
            // XXX: Setting this caused glitches in the nvidia implementation
            // Always setting it to zero, produces correct results
            //info->IsLongTerm[j] = frame->flags & HEVC_FRAME_FLAG_LONG_REF;
            info->IsLongTerm[j] = 0;
            j++;
        }
    }
    /* Copy of specification field, see Section 8.3.2 of the
       H.265/HEVC Specification. */
    info->NumPocStCurrBefore = h->rps[ST_CURR_BEF].nb_refs;
    if (info->NumPocStCurrBefore > 8) {
        av_log(avctx, AV_LOG_WARNING,
             "VDPAU only supports up to 8 references in StCurrBefore. "
             "This frame may not be decoded correctly.\n");

static int grab_read_header(AVFormatContext *s1, AVFormatParameters *ap)
{
    VideoData *s = s1->priv_data;
    AVStream *st;
    int video_fd;
    int desired_palette, desired_depth;
    struct video_tuner tuner;
    struct video_audio audio;
    struct video_picture pict;
    int j;
    int vformat_num = FF_ARRAY_ELEMS(video_formats);

    if (ap->time_base.den <= 0) {
        av_log(s1, AV_LOG_ERROR, "Wrong time base (%d)\n", ap->time_base.den);
        return -1;
    }
    s->time_base = ap->time_base;

    s->video_win.width = ap->width;
    s->video_win.height = ap->height;

    st = av_new_stream(s1, 0);
    if (!st)
        return AVERROR(ENOMEM);
    av_set_pts_info(st, 64, 1, 1000000); /* 64 bits pts in us */

    video_fd = open(s1->filename, O_RDWR);
    if (video_fd < 0) {
        av_log(s1, AV_LOG_ERROR, "%s: %s\n", s1->filename, strerror(errno));
        goto fail;
    }

    if (ioctl(video_fd, VIDIOCGCAP, &s->video_cap) < 0) {
        av_log(s1, AV_LOG_ERROR, "VIDIOCGCAP: %s\n", strerror(errno));
        goto fail;
    }

    if (!(s->video_cap.type & VID_TYPE_CAPTURE)) {
        av_log(s1, AV_LOG_ERROR, "Fatal: grab device does not handle capture\n");
        goto fail;
    }

    /* no values set, autodetect them */
    if (s->video_win.width <= 0 || s->video_win.height <= 0) {
        if (ioctl(video_fd, VIDIOCGWIN, &s->video_win, sizeof(s->video_win)) < 0) {
            av_log(s1, AV_LOG_ERROR, "VIDIOCGWIN: %s\n", strerror(errno));
            goto fail;
        }
    }

    if(avcodec_check_dimensions(s1, s->video_win.width, s->video_win.height) < 0)
        return -1;

    desired_palette = -1;
    desired_depth = -1;
    for (j = 0; j < vformat_num; j++) {
        if (ap->pix_fmt == video_formats[j].pix_fmt) {
            desired_palette = video_formats[j].palette;
            desired_depth = video_formats[j].depth;
            break;
        }
    }

    /* set tv standard */
    if (ap->standard && !ioctl(video_fd, VIDIOCGTUNER, &tuner)) {
        if (!strcasecmp(ap->standard, "pal"))
            tuner.mode = VIDEO_MODE_PAL;
        else if (!strcasecmp(ap->standard, "secam"))
            tuner.mode = VIDEO_MODE_SECAM;
        else
            tuner.mode = VIDEO_MODE_NTSC;
        ioctl(video_fd, VIDIOCSTUNER, &tuner);
    }

    /* unmute audio */
    audio.audio = 0;
    ioctl(video_fd, VIDIOCGAUDIO, &audio);
    memcpy(&s->audio_saved, &audio, sizeof(audio));
    audio.flags &= ~VIDEO_AUDIO_MUTE;
    ioctl(video_fd, VIDIOCSAUDIO, &audio);

    ioctl(video_fd, VIDIOCGPICT, &pict);
#if 0
    printf("v4l: colour=%d hue=%d brightness=%d constrast=%d whiteness=%d\n",
           pict.colour,
           pict.hue,
           pict.brightness,
           pict.contrast,
           pict.whiteness);
#endif
    /* try to choose a suitable video format */
    pict.palette = desired_palette;
    pict.depth= desired_depth;
    if (desired_palette == -1 || ioctl(video_fd, VIDIOCSPICT, &pict) < 0) {
        for (j = 0; j < vformat_num; j++) {
            pict.palette = video_formats[j].palette;
            pict.depth = video_formats[j].depth;
            if (-1 != ioctl(video_fd, VIDIOCSPICT, &pict))
                break;
        }
//.........这里部分代码省略.........