Java mp4parser输出为空

2022-05-31 00:00:00 mp4 java mp4parser fmp4 mpeg

此使用案例是一项服务，它手动将一系列未压缩的.wav媒体段编码为.m4s片段以通过mpeg-dash进行广播，并使用ffmpeg将.wav压缩为.aac，并使用sannies/mp4parser将AAC音频组装为.m4s媒体片段。

我创建了this public GitHub project以完整复制该问题。

例如，下面是自定义ChunkFragmentM4sBuilder.java类。

使用MP4盒的第一个示例可以工作，因为我能够生成一个初始化的MP4+系列片段M4 然后可以串联这些文件以形成可播放的MPEG4流。

注意：此用例要求从单独生成的源段对每个媒体段进行编码，而不是使用MP4Box等工具从连续的音频源进行流媒体。

通过mp4parser手动构建媒体段的尝试总体上仍然失败，因为由下面使用的ChunkFragmentM4sBuilder.java格式不正确。但我很难理解它们到底是如何畸形的。

将两个测试日志并排比较对我很有帮助侧面，ChunkFragmentM4sBuilderTest.log.txt 和MP4BoxTest.log.txt。

通过Java mp4parser(格式错误)

前者log是来自ChunkFragmentM4sBuilderTest.java，其结果是中的串联测试输出test-java-mp4parser.mp4 事实为空：

Files.deleteIfExists(Path.of(m4sFilePath));
AACTrackImpl aacTrack=new AACTrackImpl(new FileDataSourceImpl(aacFilePath));
Movie movie=new Movie();
movie.addTrack(aacTrack);
Container mp4file=new ChunkFragmentM4sBuilder(hz,seconds,seqNum,bufferSize).build(movie);
FileChannel fc=new FileOutputStream(m4sFilePath).getChannel();
mp4file.writeContainer(fc);
fc.close();

test5.mpd
test5-128k-163493804.m4s
test5-128k-163493805.m4s
test5-128k-163493806.m4s
test5-128k-IS.mp4

串联框：

FileTypeBox[majorBrand=iso5;minorVersion=512;compatibleBrand=iso6;compatibleBrand=mp41]
MovieBox[MovieHeaderBox[creationTime=Thu Dec 31 16:00:00 PST 1903;modificationTime=Thu Dec 31 16:00:00 PST 1903;timescale=1000;duration=0;rate=1.0;volume=1.0;matrix=Rotate 0°;nextTrackId=2];TrackBox[TrackHeaderBox[creationTime=Thu Dec 31 16:00:00 PST 1903;modificationTime=Thu Dec 31 16:00:00 PST 1903;trackId=1;duration=0;layer=0;alternateGroup=1;volume=1.0;matrix=Rotate 0°;width=0.0;height=0.0];EditBox[EditListBox{entries=[Entry{segmentDuration=0, mediaTime=1024, mediaRate=1.0}]}];MediaBox[MediaHeaderBox[creationTime=Thu Dec 31 16:00:00 PST 1903;modificationTime=Thu Dec 31 16:00:00 PST 1903;timescale=48000;duration=0;language=und];HandlerBox[handlerType=soun;name=SoundHandler];MediaInformationBox[SoundMediaHeaderBox[balance=0.0];DataInformationBox[DataReferenceBox[DataEntryUrlBox[]]];SampleTableBox[SampleDescriptionBox[AudioSampleEntry{bytesPerSample=0, bytesPerFrame=0, bytesPerPacket=0, samplesPerPacket=0, packetSize=0, compressionId=0, soundVersion=0, sampleRate=48000, sampleSize=16, channelCount=2, boxes=[org.mp4parser.boxes.iso14496.part14.ESDescriptorBox@bed094d2]}];TimeToSampleBox[entryCount=0];SampleToChunkBox[entryCount=0];SampleSizeBox[sampleSize=0;sampleCount=0];StaticChunkOffsetBox[entryCount=0]]]]];MovieExtendsBox[org.mp4parser.boxes.iso14496.part12.TrackExtendsBox@11e7301d];UserDataBox[MetaBox[HandlerBox[handlerType=mdir;name=];AppleItemListBox[org.mp4parser.boxes.apple.AppleEncoderBox@691fba4]]]]
SegmentTypeBox[majorBrand=msdh;minorVersion=0;compatibleBrand=msdh;compatibleBrand=msix]
SegmentIndexBox{entries=[Entry{referenceType=0, referencedSize=160944, subsegmentDuration=480000, startsWithSap=1, sapType=0, sapDeltaTime=0}], referenceId=1, timeScale=48000, earliestPresentationTime=0, firstOffset=0, reserved=0}
MovieFragmentBox[MovieFragmentHeaderBox{sequenceNumber=151304042};TrackFragmentBox[TrackFragmentHeaderBox{trackId=1, baseDataOffset=-1, sampleDescriptionIndex=0, defaultSampleDuration=-1, defaultSampleSize=-1, defaultSampleFlags=null, durationIsEmpty=true, defaultBaseIsMoof=true};TrackFragmentBaseMediaDecodeTimeBox{baseMediaDecodeTime=0};TrackRunBox{sampleCount=470, dataOffset=-1, dataOffsetPresent=false, sampleSizePresent=true, sampleDurationPresent=true, sampleFlagsPresentPresent=false, sampleCompositionTimeOffsetPresent=false, firstSampleFlags=null}]]
org.mp4parser.boxes.iso14496.part12.MediaDataBox@3969adb0

通过MP4Box(Ok)

后者log是从MP4BoxTest.java产生串联的测试输出 test-mp4box.mp4可以。

注意，此方法对于最终用例是不可接受的，因为此hack方法输出的块中存在缺陷。

MP4Box 
  -profile live 
  -add aacFilePath 
  -dash 10000 
  -frag 10000 
  -idx ${NUM} 
  -moof-sn ${NUM} 
  -out test5.mpd 
  -segment-name test5-128k- 
  -segment-ext m4s 
  -single-traf 
  -subsegs-per-sidx 0 
  -daisy-chain 
  -single-segment 
  /tmp

test5.mpd
test5-128k-163494320.m4s
test5-128k-163494321.m4s
test5-128k-163494322.m4s
test5-128k-IS.mp4

串联框：

FileTypeBox[majorBrand=iso5;minorVersion=512;compatibleBrand=iso6;compatibleBrand=mp41]
MovieBox[MovieHeaderBox[creationTime=Thu Dec 31 16:00:00 PST 1903;modificationTime=Thu Dec 31 16:00:00 PST 1903;timescale=1000;duration=0;rate=1.0;volume=1.0;matrix=Rotate 0°;nextTrackId=2];TrackBox[TrackHeaderBox[creationTime=Thu Dec 31 16:00:00 PST 1903;modificationTime=Thu Dec 31 16:00:00 PST 1903;trackId=1;duration=0;layer=0;alternateGroup=1;volume=1.0;matrix=Rotate 0°;width=0.0;height=0.0];EditBox[EditListBox{entries=[Entry{segmentDuration=0, mediaTime=1024, mediaRate=1.0}]}];MediaBox[MediaHeaderBox[creationTime=Thu Dec 31 16:00:00 PST 1903;modificationTime=Thu Dec 31 16:00:00 PST 1903;timescale=48000;duration=0;language=und];HandlerBox[handlerType=soun;name=SoundHandler];MediaInformationBox[SoundMediaHeaderBox[balance=0.0];DataInformationBox[DataReferenceBox[DataEntryUrlBox[]]];SampleTableBox[SampleDescriptionBox[AudioSampleEntry{bytesPerSample=0, bytesPerFrame=0, bytesPerPacket=0, samplesPerPacket=0, packetSize=0, compressionId=0, soundVersion=0, sampleRate=48000, sampleSize=16, channelCount=2, boxes=[org.mp4parser.boxes.iso14496.part14.ESDescriptorBox@bed094d2]}];TimeToSampleBox[entryCount=0];SampleToChunkBox[entryCount=0];SampleSizeBox[sampleSize=0;sampleCount=0];StaticChunkOffsetBox[entryCount=0]]]]];MovieExtendsBox[org.mp4parser.boxes.iso14496.part12.TrackExtendsBox@7ce1e496];UserDataBox[MetaBox[HandlerBox[handlerType=mdir;name=];AppleItemListBox[org.mp4parser.boxes.apple.AppleEncoderBox@51da5351]]]]
SegmentTypeBox[majorBrand=msdh;minorVersion=0;compatibleBrand=msdh;compatibleBrand=msix]
SegmentIndexBox{entries=[Entry{referenceType=0, referencedSize=162267, subsegmentDuration=479232, startsWithSap=1, sapType=1, sapDeltaTime=0}], referenceId=1, timeScale=48000, earliestPresentationTime=0, firstOffset=0, reserved=0}
MovieFragmentBox[MovieFragmentHeaderBox{sequenceNumber=151304042};TrackFragmentBox[TrackFragmentHeaderBox{trackId=1, baseDataOffset=-1, sampleDescriptionIndex=0, defaultSampleDuration=-1, defaultSampleSize=-1, defaultSampleFlags=null, durationIsEmpty=false, defaultBaseIsMoof=true};TrackFragmentBaseMediaDecodeTimeBox{baseMediaDecodeTime=0};TrackRunBox{sampleCount=468, dataOffset=1964, dataOffsetPresent=true, sampleSizePresent=true, sampleDurationPresent=false, sampleFlagsPresentPresent=false, sampleCompositionTimeOffsetPresent=false, firstSampleFlags=null}]]
org.mp4parser.boxes.iso14496.part12.MediaDataBox@640d3ba5

解决方案

test-java-mp4parser.mp4不为空，但无效，原因是：

sidx条目引用大小错误
tfhd正在使用0覆盖默认的样本说明索引(1)
trun未指定数据偏移量
mdatAAC数据以8个零字节开始，导致解码失败

如果FFmpeg已修复，则使用FFmpeg播放文件。

列出的m4s段的格式也不正确，似乎与串联结果不一致。例如，序列号用作样本描述索引。

相关文章