public ITag ReadTag()
{
lock (this.SyncRoot)
{
ITag tag = null;
//empty-out the pre-streaming tags first
if (_firstTags.Count > 0)
{
//log.debug("Returning pre-tag");
// Return first tags before media data
tag = _firstTags.First.Value;
_firstTags.RemoveFirst();
return(tag);
}
//log.debug("Read tag - sample {} prevFrameSize {} audio: {} video: {}", new Object[]{currentSample, prevFrameSize, audioCount, videoCount});
//get the current frame
Mp4Frame frame = _frames[_currentFrame];
#if LOGGING
log.Debug(string.Format("Playback #{0} {1}", _currentFrame, frame));
#endif
int sampleSize = frame.Size;
int time = (int)Math.Round(frame.Time * 1000.0);
//log.debug("Read tag - dst: {} base: {} time: {}", new Object[]{frameTs, baseTs, time});
long samplePos = frame.Offset;
//log.debug("Read tag - samplePos {}", samplePos);
//determine frame type and packet body padding
byte type = frame.Type;
//create a byte buffer of the size of the sample
byte[] data = new byte[sampleSize + 2];
try
{
Array.Copy(Mp4Reader.PREFIX_AUDIO_FRAME, data, Mp4Reader.PREFIX_AUDIO_FRAME.Length);
//do we need to add the mdat offset to the sample position?
_fs.Position = samplePos;
_fs.Read(data, Mp4Reader.PREFIX_AUDIO_FRAME.Length, sampleSize);
}
catch (Exception ex)
{
#if LOGGING
log.Error("Error on channel position / read", ex);
#endif
}
//create the tag
tag = new Tag(type, time, data.Length, data, _prevFrameSize);
//increment the frame number
_currentFrame++;
//set the frame / tag size
_prevFrameSize = tag.BodySize;
//log.debug("Tag: {}", tag);
return(tag);
}
}
/// <summary>
/// Performs frame analysis and generates metadata for use in seeking. All the frames are analyzed and sorted together based on time and offset.
/// </summary>
public void AnalyzeFrames()
{
#if LOGGING
log.Debug("Analyzing frames");
#endif
// tag == sample
int sample = 1;
long pos = 0;
//add the audio frames / samples / chunks
for (int i = 0; i < _audioSamplesToChunks.Count; i++)
{
Mp4Atom.Record record = _audioSamplesToChunks[i];
int firstChunk = record.FirstChunk;
int lastChunk = _audioChunkOffsets.Count;
if (i < _audioSamplesToChunks.Count - 1)
{
Mp4Atom.Record nextRecord = _audioSamplesToChunks[i + 1];
lastChunk = nextRecord.FirstChunk - 1;
}
for (int chunk = firstChunk; chunk <= lastChunk; chunk++)
{
int sampleCount = record.SamplesPerChunk;
pos = _audioChunkOffsets[chunk - 1];
while (sampleCount > 0)
{
//calculate ts
double ts = (_audioSampleDuration * (sample - 1)) / _audioTimeScale;
//sample size
int size = _audioSamples[sample - 1];
//create a frame
Mp4Frame frame = new Mp4Frame();
frame.Offset = pos;
frame.Size = size;
frame.Time = ts;
frame.Type = IOConstants.TYPE_AUDIO;
_frames.Add(frame);
//log.debug("Sample #{} {}", sample, frame);
//inc and dec stuff
pos += size;
sampleCount--;
sample++;
}
}
}
//sort the frames
_frames.Sort();
#if LOGGING
log.Debug(string.Format("Frames count: {0}", _frames.Count));
#endif
}
/// <summary>
/// Performs frame analysis and generates metadata for use in seeking. All the frames are analyzed and sorted together based on time and offset.
/// </summary>
public void AnalyzeFrames()
{
#if !SILVERLIGHT
log.Debug("Analyzing frames");
#endif
// Maps positions, samples, timestamps to one another
_timePosMap = new Dictionary<int, long>();
_samplePosMap = new Dictionary<int, long>();
// tag == sample
int sample = 1;
long pos;
for (int i = 0; i < _videoSamplesToChunks.Count; i++)
{
Mp4Atom.Record record = _videoSamplesToChunks[i];
int firstChunk = record.FirstChunk;
int lastChunk = _videoChunkOffsets.Count;
if (i < _videoSamplesToChunks.Count - 1)
{
Mp4Atom.Record nextRecord = _videoSamplesToChunks[i + 1];
lastChunk = nextRecord.FirstChunk - 1;
}
for (int chunk = firstChunk; chunk <= lastChunk; chunk++)
{
int sampleCount = record.SamplesPerChunk;
pos = _videoChunkOffsets[chunk - 1];
while (sampleCount > 0)
{
//log.debug("Position: {}", pos);
_samplePosMap.Add(sample, pos);
//calculate ts
double ts = (_videoSampleDuration * (sample - 1)) / _videoTimeScale;
//check to see if the sample is a keyframe
bool keyframe = false;
//some files appear not to have sync samples
if (_syncSamples != null)
{
keyframe = _syncSamples.Contains(sample);
if (_seekPoints == null)
{
_seekPoints = new LinkedList<int>();
}
int keyframeTs = (int)Math.Round(ts * 1000.0);
_seekPoints.AddLast(keyframeTs);
_timePosMap.Add(keyframeTs, pos);
}
//size of the sample
int size = _videoSamples[sample - 1];
//create a frame
Mp4Frame frame = new Mp4Frame();
frame.IsKeyFrame = keyframe;
frame.Offset = pos;
frame.Size = size;
frame.Time = ts;
frame.Type = IOConstants.TYPE_VIDEO;
_frames.Add(frame);
//log.debug("Sample #{} {}", sample, frame);
//inc and dec stuff
pos += size;
sampleCount--;
sample++;
}
}
}
//log.debug("Sample position map (video): {}", samplePosMap);
//add the audio frames / samples / chunks
sample = 1;
for (int i = 0; i < _audioSamplesToChunks.Count; i++)
{
Mp4Atom.Record record = _audioSamplesToChunks[i];
int firstChunk = record.FirstChunk;
int lastChunk = _audioChunkOffsets.Count;
if (i < _audioSamplesToChunks.Count - 1)
{
Mp4Atom.Record nextRecord = _audioSamplesToChunks[i + 1];
lastChunk = nextRecord.FirstChunk - 1;
}
for (int chunk = firstChunk; chunk <= lastChunk; chunk++)
{
int sampleCount = record.SamplesPerChunk;
pos = _audioChunkOffsets[chunk - 1];
while (sampleCount > 0)
{
//calculate ts
double ts = (_audioSampleDuration * (sample - 1)) / _audioTimeScale;
//sample size
int size = _audioSamples[sample - 1];
//create a frame
Mp4Frame frame = new Mp4Frame();
frame.Offset = pos;
frame.Size = size;
frame.Time = ts;
frame.Type = IOConstants.TYPE_AUDIO;
_frames.Add(frame);
//log.debug("Sample #{} {}", sample, frame);
//inc and dec stuff
pos += size;
sampleCount--;
sample++;
}
}
}
//sort the frames
_frames.Sort();
#if !SILVERLIGHT
log.Debug(string.Format("Frames count: {0}", _frames.Count));
//log.debug("Frames: {}", frames);
#endif
//release some memory, since we're done with the vectors
_audioChunkOffsets.Clear();
_audioChunkOffsets = null;
_audioSamplesToChunks.Clear();
_audioSamplesToChunks = null;
_videoChunkOffsets.Clear();
_videoChunkOffsets = null;
_videoSamplesToChunks.Clear();
_videoSamplesToChunks = null;
_syncSamples.Clear();
_syncSamples = null;
}
/// <summary>
/// Performs frame analysis and generates metadata for use in seeking. All the frames are analyzed and sorted together based on time and offset.
/// </summary>
public void AnalyzeFrames() {
log.Debug("Analyzing frames");
// tag == sample
int sample = 1;
long pos = 0;
//add the audio frames / samples / chunks
for (int i = 0; i < _audioSamplesToChunks.Count; i++) {
Mp4Atom.Record record = _audioSamplesToChunks[i];
int firstChunk = record.FirstChunk;
int lastChunk = _audioChunkOffsets.Count;
if (i < _audioSamplesToChunks.Count - 1) {
Mp4Atom.Record nextRecord = _audioSamplesToChunks[i + 1];
lastChunk = nextRecord.FirstChunk - 1;
}
for (int chunk = firstChunk; chunk <= lastChunk; chunk++) {
int sampleCount = record.SamplesPerChunk;
pos = _audioChunkOffsets[chunk - 1];
while (sampleCount > 0) {
//calculate ts
double ts = (_audioSampleDuration * (sample - 1)) / _audioTimeScale;
//sample size
int size = _audioSamples[sample - 1];
//create a frame
Mp4Frame frame = new Mp4Frame();
frame.Offset = pos;
frame.Size = size;
frame.Time = ts;
frame.Type = IOConstants.TYPE_AUDIO;
_frames.Add(frame);
//log.debug("Sample #{} {}", sample, frame);
//inc and dec stuff
pos += size;
sampleCount--;
sample++;
}
}
}
//sort the frames
_frames.Sort();
log.Debug(string.Format("Frames count: {0}", _frames.Count));
}
