C++ BMediaTrack::CurrentTime方法代码示例

//.........这里部分代码省略.........
	gsFormat.format = format.u.raw_audio.format;
	gsFormat.byte_order = format.u.raw_audio.byte_order;

	BPushGameSound pushGameSound(framesPerBufferPart, &gsFormat,
		bufferPartCount);
	if (pushGameSound.InitCheck() != B_OK) {
		printf("trouble initializing push game sound: %s\n",
			strerror(pushGameSound.InitCheck()));
		return 1;
	}

	uint8 *buffer;
	size_t bufferSize;
	if (pushGameSound.LockForCyclic((void **)&buffer, &bufferSize)
			!= BPushGameSound::lock_ok) {
		printf("cannot lock buffer\n");
		return 1;
	}
	memset(buffer, 0, bufferSize);

	if (pushGameSound.StartPlaying() != B_OK) {
		printf("cannot start playback\n");
		return 1;
	}

	printf("playing, press [esc] to exit...\n");

	uint8 decoded[format.u.raw_audio.buffer_size * 2];
	size_t bufferPartSize = framesPerBufferPart
		* format.u.raw_audio.channel_count
		* (format.u.raw_audio.format
			& media_raw_audio_format::B_AUDIO_SIZE_MASK);
	size_t decodedSize = 0;
	size_t partPos = 0;
	size_t pos = 0; /*pushGameSound.CurrentPosition();*/
	key_info keyInfo;

	while (true) {
		// fill buffer part with data from decoded buffer
		while (partPos < bufferPartSize && decodedSize) {
			size_t size = min_c(bufferPartSize - partPos, decodedSize);

			memcpy(buffer + pos + partPos, decoded, size);
			partPos += size;

			decodedSize -= size;
			memmove(decoded, decoded + size, decodedSize);
		}

		// if there are too little data to fill next buffer part
		// read next decoded frames
		if (partPos < bufferPartSize) {
			int64 frameCount;
			if (mediaTrack->ReadFrames(decoded + decodedSize, &frameCount)
					!= B_OK)
				break;
			if (frameCount == 0)
				break;

			decodedSize += frameCount * format.u.raw_audio.channel_count
				* (format.u.raw_audio.format
					& media_raw_audio_format::B_AUDIO_SIZE_MASK);

			printf("\rtime: %.2f",
				(double)mediaTrack->CurrentTime() / 1000000LL);
			fflush(stdout);

			continue;
		}

		// this buffer part is done
		partPos = 0;
		pos += bufferPartSize;
		if (bufferSize <= pos)
			pos = 0;

		// playback sync - wait for the buffer part we're about to fill to be
		// played
		while (pushGameSound.CurrentPosition() >= pos + bufferPartSize
			|| pushGameSound.CurrentPosition() < pos)
			snooze(1000 * framesPerBufferPart / gsFormat.frame_rate);

		// check escape key state
		if (get_key_info(&keyInfo) != B_OK) {
			printf("\nkeyboard state read error\n");
			break;
		}
		if ((keyInfo.key_states[0] & 0x40) != 0)
			break;
	}

	pushGameSound.StopPlaying();

	mediaFile.ReleaseTrack(mediaTrack);
	mediaFile.CloseFile();

	printf("\nfinished.\n");

	return 0;
}

int32
MediaView::MediaPlayer(
	void	*arg)
{
	MediaView*		view = (MediaView *)arg;
	BWindow*		window = view->Window();
	BBitmap*		bitmap = view->fBitmap;
	BMediaTrack*	videoTrack = view->fVideoTrack;
	BMediaTrack*	audioTrack = view->fAudioTrack;
	BMediaTrack*	counterTrack = (videoTrack != NULL) ? videoTrack : audioTrack;
	AudioOutput*	audioOutput = view->fAudioOutput;
	void*			adBuffer = view->fAudioDumpingBuffer;
	int64			numFrames = counterTrack->CountFrames();
	int64			numFramesToSkip = 0;
	int64			numSkippedFrames = 0;
	bool			scrubbing = false;
	bool			seekNeeded = false;
	int64			dummy;
	media_header	mh;
	bigtime_t		vStartTime, aStartTime, seekTime, snoozeTime, startTime;
	bigtime_t		curScrubbing, lastScrubbing, lastTime;

	curScrubbing = lastScrubbing = system_time();
	seekTime = 0LL;

	// Main processing loop (handle stop->start->stop)
	while (acquire_sem(view->fPlaySem) == B_OK) {
		release_sem(view->fPlaySem);
		
		// as we are doing stop->start, restart audio if needed.
		if (audioTrack != NULL)
			audioOutput->Play();
		startTime = system_time()-counterTrack->CurrentTime();		

		// This will loop until the end of the stream
		while ((counterTrack->CurrentFrame() < numFrames) || scrubbing) {
		
			// We are in scrub mode
			if (acquire_sem(view->fScrubSem) == B_OK) {
				curScrubbing = system_time();

				// We are entering scrub mode
				if (!scrubbing) {
					if (audioTrack != NULL)
						audioOutput->Stop();
					scrubbing = true;
				}
				// Do a seek.
				seekNeeded = true;
				seekTime = view->fScrubTime;
			}
			// We are not scrubbing
			else if (scrubbing) {
				if (audioTrack != NULL)
					audioOutput->Play();
				scrubbing = false;
			}
			
			// Handle seeking
			if (seekNeeded) {
				if (videoTrack) {
					// Seek the seekTime as close as possible
					vStartTime = seekTime;
					videoTrack->SeekToTime(&vStartTime);
					
					// Read frames until we get less than 50ms ahead.
					lastTime = vStartTime;
					do {
						bitmap->LockBits();
						status_t err = videoTrack->ReadFrames((char*)bitmap->Bits(), &dummy, &mh);
						bitmap->UnlockBits();
						if (err != B_OK) break;
						vStartTime = mh.start_time;
						if ((dummy == 0) || (vStartTime <= lastTime))
							break;
						lastTime = vStartTime;
					} while (seekTime - vStartTime > 50000);
				}
				
				if (audioTrack) {
					// Seek the extractor as close as possible
					aStartTime = seekTime;
					audioOutput->SeekToTime(&aStartTime);
					
					// Read frames until we get less than 50ms ahead.
					lastTime = aStartTime;
					while (seekTime - aStartTime > 50000) {
						if (audioTrack->ReadFrames((char *)adBuffer, &dummy, &mh) != B_OK)
							break;
						aStartTime = mh.start_time;
						if ((dummy == 0) || (aStartTime <= lastTime))
							break;
						lastTime = aStartTime;
					}
				}
				else startTime = system_time() - vStartTime;
				
				// Set the current time
				view->fCurTime = seekTime;	
			
//.........这里部分代码省略.........