/// <summary>
/// Loads M4ESDAtom atom from the input bitstream.
/// </summary>
/// <param name="bitstream">The input bitstream.</param>
/// <returns>The number of bytes loaded.</returns>
public long create_esd_atom(Mp4DataStream bitstream) {
create_full_atom(bitstream);
esd_descriptor = Mp4Descriptor.CreateDescriptor(bitstream);
_bytesRead += esd_descriptor.BytesRead;
return _bytesRead;
}
/// <summary>
/// This handles the moov atom being at the beginning or end of the file, so the mdat may also be before or after the moov atom.
/// </summary>
public void DecodeHeader()
{
try
{
// the first atom will/should be the type
Mp4Atom type = Mp4Atom.CreateAtom(_inputStream);
// expect ftyp
#if LOGGING
log.Debug(string.Format("Type {0}", type));
#endif
// keep a running count of the number of atoms found at the "top" levels
int topAtoms = 0;
// we want a moov and an mdat, anything else throw the invalid file type error
while (topAtoms < 2)
{
Mp4Atom atom = Mp4Atom.CreateAtom(_inputStream);
switch (atom.Type)
{
case 1836019574: //moov
topAtoms++;
Mp4Atom moov = atom;
// expect moov
#if LOGGING
log.Debug(string.Format("Type {0}", moov));
#endif
//log.debug("moov children: {}", moov.getChildren());
_moovOffset = _inputStream.Offset - moov.Size;
Mp4Atom mvhd = moov.Lookup(Mp4Atom.TypeToInt("mvhd"), 0);
if (mvhd != null)
{
#if LOGGING
log.Debug("Movie header atom found");
#endif
//get the initial timescale
_timeScale = mvhd.TimeScale;
_duration = mvhd.Duration;
#if LOGGING
log.Debug(string.Format("Time scale {0} Duration {1}", _timeScale, _duration));
#endif
}
/* nothing needed here yet
* MP4Atom meta = moov.lookup(MP4Atom.typeToInt("meta"), 0);
* if (meta != null) {
* log.debug("Meta atom found");
* log.debug("{}", ToStringBuilder.reflectionToString(meta));
* }
*/
Mp4Atom trak = moov.Lookup(Mp4Atom.TypeToInt("trak"), 0);
if (trak != null)
{
#if LOGGING
log.Debug("Track atom found");
#endif
//log.debug("trak children: {}", trak.getChildren());
// trak: tkhd, edts, mdia
Mp4Atom edts = trak.Lookup(Mp4Atom.TypeToInt("edts"), 0);
if (edts != null)
{
#if LOGGING
log.Debug("Edit atom found");
#endif
//log.debug("edts children: {}", edts.getChildren());
}
Mp4Atom mdia = trak.Lookup(Mp4Atom.TypeToInt("mdia"), 0);
if (mdia != null)
{
#if LOGGING
log.Debug("Media atom found");
#endif
// mdia: mdhd, hdlr, minf
int scale = 0;
//get the media header atom
Mp4Atom mdhd = mdia.Lookup(Mp4Atom.TypeToInt("mdhd"), 0);
if (mdhd != null)
{
#if LOGGING
log.Debug("Media data header atom found");
#endif
//this will be for either video or audio depending media info
scale = mdhd.TimeScale;
#if LOGGING
log.Debug(string.Format("Time scale {0}", scale));
#endif
}
Mp4Atom hdlr = mdia.Lookup(Mp4Atom.TypeToInt("hdlr"), 0);
if (hdlr != null)
{
#if LOGGING
log.Debug("Handler ref atom found");
#endif
// soun or vide
#if LOGGING
log.Debug(string.Format("Handler type: {0}", Mp4Atom.IntToType(hdlr.HandlerType)));
#endif
String hdlrType = Mp4Atom.IntToType(hdlr.HandlerType);
if ("soun".Equals(hdlrType))
{
if (scale > 0)
{
_audioTimeScale = scale * 1.0;
#if LOGGING
log.Debug(string.Format("Audio time scale: {0}", _audioTimeScale));
#endif
}
}
}
Mp4Atom minf = mdia.Lookup(Mp4Atom.TypeToInt("minf"), 0);
if (minf != null)
{
#if LOGGING
log.Debug("Media info atom found");
#endif
// minf: (audio) smhd, dinf, stbl / (video) vmhd,
// dinf, stbl
Mp4Atom smhd = minf.Lookup(Mp4Atom.TypeToInt("smhd"), 0);
if (smhd != null)
{
#if LOGGING
log.Debug("Sound header atom found");
#endif
Mp4Atom dinf = minf.Lookup(Mp4Atom.TypeToInt("dinf"), 0);
if (dinf != null)
{
#if LOGGING
log.Debug("Data info atom found");
#endif
// dinf: dref
//log.Debug("Sound dinf children: {}", dinf.getChildren());
Mp4Atom dref = dinf.Lookup(Mp4Atom.TypeToInt("dref"), 0);
if (dref != null)
{
#if LOGGING
log.Debug("Data reference atom found");
#endif
}
}
Mp4Atom stbl = minf.Lookup(Mp4Atom.TypeToInt("stbl"), 0);
if (stbl != null)
{
#if LOGGING
log.Debug("Sample table atom found");
#endif
// stbl: stsd, stts, stss, stsc, stsz, stco,
// stsh
//log.debug("Sound stbl children: {}", stbl.getChildren());
// stsd - sample description
// stts - time to sample
// stsc - sample to chunk
// stsz - sample size
// stco - chunk offset
//stsd - has codec child
Mp4Atom stsd = stbl.Lookup(Mp4Atom.TypeToInt("stsd"), 0);
if (stsd != null)
{
//stsd: mp4a
#if LOGGING
log.Debug("Sample description atom found");
#endif
Mp4Atom mp4a = stsd.Children[0];
//could set the audio codec here
SetAudioCodecId(Mp4Atom.IntToType(mp4a.Type));
//log.debug("{}", ToStringBuilder.reflectionToString(mp4a));
#if LOGGING
log.Debug(string.Format("Sample size: {0}", mp4a.SampleSize));
#endif
int ats = mp4a.TimeScale;
//skip invalid audio time scale
if (ats > 0)
{
_audioTimeScale = ats * 1.0;
}
_audioChannels = mp4a.ChannelCount;
#if LOGGING
log.Debug(string.Format("Sample rate (audio time scale): {0}", _audioTimeScale));
#endif
#if LOGGING
log.Debug(string.Format("Channels: {0}", _audioChannels));
#endif
//mp4a: esds
if (mp4a.Children.Count > 0)
{
#if LOGGING
log.Debug("Elementary stream descriptor atom found");
#endif
Mp4Atom esds = mp4a.Children[0];
//log.debug("{}", ToStringBuilder.reflectionToString(esds));
Mp4Descriptor descriptor = esds.EsdDescriptor;
//log.debug("{}", ToStringBuilder.reflectionToString(descriptor));
if (descriptor != null)
{
List <Mp4Descriptor> children = descriptor.Children;
for (int e = 0; e < children.Count; e++)
{
Mp4Descriptor descr = children[e];
//log.debug("{}", ToStringBuilder.reflectionToString(descr));
if (descr.Children.Count > 0)
{
List <Mp4Descriptor> children2 = descr.Children;
for (int e2 = 0; e2 < children2.Count; e2++)
{
Mp4Descriptor descr2 = children2[e2];
//log.debug("{}", ToStringBuilder.reflectionToString(descr2));
if (descr2.Type == Mp4Descriptor.MP4DecSpecificInfoDescriptorTag)
{
//we only want the MP4DecSpecificInfoDescriptorTag
_audioDecoderBytes = descr2.DSID;
//compare the bytes to get the aacaot/aottype
//match first byte
switch (_audioDecoderBytes[0])
{
case 0x12:
default:
//AAC LC - 12 10
_audioCodecType = 1;
break;
case 0x0a:
//AAC Main - 0A 10
_audioCodecType = 0;
break;
case 0x11:
case 0x13:
//AAC LC SBR - 11 90 & 13 xx
_audioCodecType = 2;
break;
}
//we want to break out of top level for loop
e = 99;
break;
}
}
}
}
}
}
}
//stsc - has Records
Mp4Atom stsc = stbl.Lookup(Mp4Atom.TypeToInt("stsc"), 0);
if (stsc != null)
{
#if LOGGING
log.Debug("Sample to chunk atom found");
#endif
_audioSamplesToChunks = stsc.Records;
#if LOGGING
log.Debug(string.Format("Record count: {0}", _audioSamplesToChunks.Count));
#endif
Mp4Atom.Record rec = _audioSamplesToChunks[0];
#if LOGGING
log.Debug(string.Format("Record data: Description index={0} Samples per chunk={1}", rec.SampleDescriptionIndex, rec.SamplesPerChunk));
#endif
}
//stsz - has Samples
Mp4Atom stsz = stbl.Lookup(Mp4Atom.TypeToInt("stsz"), 0);
if (stsz != null)
{
#if LOGGING
log.Debug("Sample size atom found");
#endif
_audioSamples = stsz.Samples;
//vector full of integers
#if LOGGING
log.Debug(string.Format("Sample size: {0}", stsz.SampleSize));
#endif
#if LOGGING
log.Debug(string.Format("Sample count: {0}", _audioSamples.Count));
#endif
}
//stco - has Chunks
Mp4Atom stco = stbl.Lookup(Mp4Atom.TypeToInt("stco"), 0);
if (stco != null)
{
#if LOGGING
log.Debug("Chunk offset atom found");
#endif
//vector full of integers
_audioChunkOffsets = stco.Chunks;
#if LOGGING
log.Debug(string.Format("Chunk count: {0}", _audioChunkOffsets.Count));
#endif
}
//stts - has TimeSampleRecords
Mp4Atom stts = stbl.Lookup(Mp4Atom.TypeToInt("stts"), 0);
if (stts != null)
{
#if LOGGING
log.Debug("Time to sample atom found");
#endif
List <Mp4Atom.TimeSampleRecord> records = stts.TimeToSamplesRecords;
#if LOGGING
log.Debug(string.Format("Record count: {0}", records.Count));
#endif
Mp4Atom.TimeSampleRecord rec = records[0];
#if LOGGING
log.Debug(string.Format("Record data: Consecutive samples={0} Duration={1}", rec.ConsecutiveSamples, rec.SampleDuration));
#endif
//if we have 1 record then all samples have the same duration
if (records.Count > 1)
{
//TODO: handle audio samples with varying durations
#if LOGGING
log.Debug("Audio samples have differing durations, audio playback may fail");
#endif
}
_audioSampleDuration = rec.SampleDuration;
}
}
}
}
}
}
//real duration
StringBuilder sb = new StringBuilder();
double clipTime = ((double)_duration / (double)_timeScale);
#if LOGGING
log.Debug(string.Format("Clip time: {0}", clipTime));
#endif
int minutes = (int)(clipTime / 60);
if (minutes > 0)
{
sb.Append(minutes);
sb.Append('.');
}
//formatter for seconds / millis
//NumberFormat df = DecimalFormat.getInstance();
//df.setMaximumFractionDigits(2);
//sb.append(df.format((clipTime % 60)));
sb.Append(clipTime % 60);
_formattedDuration = sb.ToString();
#if LOGGING
log.Debug(string.Format("Time: {0}", _formattedDuration));
#endif
break;
case 1835295092: //mdat
topAtoms++;
long dataSize = 0L;
Mp4Atom mdat = atom;
dataSize = mdat.Size;
//log.debug("{}", ToStringBuilder.reflectionToString(mdat));
_mdatOffset = _inputStream.Offset - dataSize;
#if LOGGING
log.Debug(string.Format("File size: {0} mdat size: {1}", _file.Length, dataSize));
#endif
break;
case 1718773093: //free
case 2003395685: //wide
break;
default:
#if LOGGING
log.Warn(string.Format("Unexpected atom: {}", Mp4Atom.IntToType(atom.Type)));
#endif
break;
}
}
//add the tag name (size) to the offsets
_moovOffset += 8;
_mdatOffset += 8;
#if LOGGING
log.Debug(string.Format("Offsets moov: {0} mdat: {1}", _moovOffset, _mdatOffset));
#endif
}
catch (Exception ex)
{
#if LOGGING
log.Error("Exception decoding header / atoms", ex);
#endif
}
}