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• Cannot decode H.264 stream (Annex.B) using FFmpeg

  15 décembre 2014, par user849642

  Recently I’m writing a client of a IP camera providing H.264 stream. I’m now using FFmpeg 2.1.1 to decode the stream provided by the camera.

  Here’s some code of the application :

  Initialization :

      private unsafe void InitFFmpeg()
  
      {
  
          FFmpeg.avcodec_register_all();
  
          var codec = FFmpeg.avcodec_find_decoder(AVCodecID.AV_CODEC_ID_H264);
  
          avcodec = (IntPtr)codec;
  
  
  
          var ctx=FFmpeg.avcodec_alloc_context3(avcodec);
  
          avcontext = (IntPtr)ctx;
  
  
  
          ctx->codec = avcodec;
  
          ctx->pix_fmt = AVPixelFormat.PIX_FMT_YUV420P;
  
          ctx->flags2 |= 0x00008000;//CODEC_FLAG2_CHUNKS
  
  
  
          var options = IntPtr.Zero;
  
          int result = FFmpeg.avcodec_open2(avcontext, avcodec, ref options);
  
          avframe = FFmpeg.av_frame_alloc();
  
          avparser = FFmpeg.av_parser_init(AVCodecID.AV_CODEC_ID_H264);
  
          FFmpeg.av_init_packet(ref avpacket);
  
          inBuffer = Marshal.AllocHGlobal(300 * 1024);
  
      }

  Decoding :

      private void Decode(byte[] data, int size)
  
      {
  
          IntPtr pOut = IntPtr.Zero;
  
          int outLen = 0;
  
  
  
          Marshal.Copy(data, 0, inBuffer, size);
  
  
  
          int gotPicture = 0;
  
  
  
          var rs = FFmpeg.av_parser_parse2(avparser, avcontext, ref pOut, ref outLen, inBuffer, size, 0, 0, 0);
  
          if (outLen <= 0 || pOut.ToInt32() <= 0)
  
          {
  
              //no enough data to construct a frame, return and receive next NAL unit.
  
              return;
  
          }
  
          avpacket.data = pOut;
  
          avpacket.size = outLen;
  
          avpacket.flags |= PacketFlags.Key;
  
          var len = FFmpeg.avcodec_decode_video2(avcontext, avframe, ref gotPicture, ref avpacket);
  
          Console.WriteLine("avcodec_decode_video2 returned " + len);
  
          if (gotPicture != 0)
  
          {
  
              //some YUV to RGB stuff
  
          }
  
      }

  With the code above, I can get some output like :

  NAL unit 1: resolution=1280x720, key-frame=True, size=26.
  
  NAL unit 2: resolution=1280x720, key-frame=False, size=8.
  
  NAL unit 3: resolution=1280x720, key-frame=False, size=97222.
  
  NAL unit 4: resolution=1280x720, key-frame=False, size=14129.
  
  avcodec_decode_video2 returned 1
  
  NAL unit 5: resolution=1280x720, key-frame=False, size=12522.
  
  NAL unit 6: resolution=1280x720, key-frame=False, size=12352.
  
  avcodec_decode_video2 returned 1
  
  NAL unit 7: resolution=1280x720, key-frame=False, size=12291.
  
  NAL unit 8: resolution=1280x720, key-frame=False, size=12182.

  From the ouput I can see the parser can recognize the NAL units sent by the camera and can construct frames from them.

  NAL unit 1 to 4 are slices of a key frame containing SPS/PPS, and the following 2 NAL units form a normal frame.

  And the avcodec_decode_video2 function doesn’t produce any error, but just keep returning 1 and gotPicture is alway 0.

  If I clear AVCodecContext.flags2, it starts to complain that the packet I provided contains no frame :

  NAL unit 100: resolution=1280x720, frame-rate=0, key-frame=True, size=26.
  
  NAL unit 101: resolution=1280x720, frame-rate=0, key-frame=False, size=8.
  
  NAL unit 102: resolution=1280x720, frame-rate=0, key-frame=False, size=96927.
  
  NAL unit 103: resolution=1280x720, frame-rate=0, key-frame=False, size=17149.
  
  [h264 @ 01423440] no frame!
  
  avcodec_decode_video2 returned -1094995529
  
  NAL unit 104: resolution=1280x720, frame-rate=0, key-frame=False, size=12636.
  
  NAL unit 105: resolution=1280x720, frame-rate=0, key-frame=False, size=12338.
  
  [h264 @ 01423440] no frame!

  If I write the raw stream to a file, I can use FFmpeg to mux the stream to an mp4 container, and can play the mp4 file with any player.

  The raw data I received is something like :

  00 00 00 01 67 42 00 28 E9 00 A0 0B 75 C4 80 03 6E E8 00 CD FE 60 0D 88 10 94
  
  00 00 00 01 68 CE 31 52
  
  00 00 00 01 65 88 81 00 06 66 36 25 11 21 2C 04 3B 81 E1 80 00 85 4B 23 9F 71...
  
  ...

• Concat two mp4 files with MP4Box error : Bad Parameter [on hold]

  6 février 2014, par user3279646

  I'm trying to concat two mp4 files. But I get an error : Bad Parameter

  Can someone help me with this problem ?

  I'm using de debian packages. On a previously version it worked fine. I moved from a old debian version to the new one and I also had to change the ffmpeg to avconv which I use to create these mp4 files. I also had to change the audio codec to '-acodec aac -strict experimental'

  Kind Regards,
  Marcel

      MP4Box -force-cat -cat conv1-1391608417314.mp4 -add conv1-1391608417345.mp4 -new output.mp4
  
      IsoMedia import - track ID 1 - Video (size 384 x 288)
  
      Error importing conv1-1391608417345.mp4: Bad Parameter

  ---

      MP4Box -info conv1-1391608417314.mp4
  
      Movie Info 
  
      Timescale 1000 - Duration 00:00:23.985
  
      Fragmented File no - 2 track(s)
  
      File Brand isom - version 512
  
      Created: UNKNOWN DATE
  
      File has root IOD (9 bytes)
  
      Scene PL 0xff - Graphics PL 0xff - OD PL 0xff
  
      Visual PL: Not part of MPEG-4 Visual profiles (0xfe)
  
      Audio PL: Not part of MPEG-4 audio profiles (0xfe)
  
      No streams included in root OD
  
  
  
      iTunes Info:
  
      Encoder Software: Lavf53.21.1
  
  
  
      Track # 1 Info - TrackID 1 - TimeScale 1000 - Duration 00:00:23.985
  
      Media Info: Language "Undetermined" - Type "vide:avc1" - 23988 samples
  
      Visual Track layout: x=0 y=0 width=384 height=288
  
      MPEG-4 Config: Visual Stream - ObjectTypeIndication 0x21
  
      AVC/H264 Video - Visual Size 384 x 288
  
      AVC Info: 1 SPS - 1 PPS - Profile High @ Level 4.2
  
      NAL Unit length bits: 32
  
      Self-synchronized
  
  
  
      Track # 2 Info - TrackID 2 - TimeScale 44100 - Duration 00:00:23.962
  
      Media Info: Language "Undetermined" - Type "soun:mp4a" - 1032 samples
  
      MPEG-4 Config: Audio Stream - ObjectTypeIndication 0x40
  
      MPEG-4 Audio MPEG-4 Audio AAC LC - 2 Channel(s) - SampleRate 44100
  
      Synchronized on stream 1
  
      Alternate Group ID 1

  ---

      MP4Box -version
  
      MP4Box - GPAC version 0.5.0-rev
  
      GPAC Copyright: (c) Jean Le Feuvre 2000-2005
  
      (c) ENST 2005-200X
  
      GPAC Configuration: --build=x86_64-linux-gnu --prefix=/usr --includedir=${prefix}/include --mandir=${prefix}/share/man --infodir=${prefix}/share/info --sysconfdir=/etc --localstatedir=/var --libdir=${prefix}/lib/x86_64-linux-gnu --libexecdir=${prefix}/lib/x86_64-linux-gnu --disable-maintainer-mode --disable-dependency-tracking --prefix=/usr --mandir=${prefix}/share/man --libdir=lib/x86_64-linux-gnu --extra-cflags='-Wall -fPIC -DPIC -I/usr/include/mozjs -DXP_UNIX' --enable-joystick --enable-debug --disable-ssl
  
      Features: GPAC_HAS_JPEG GPAC_HAS_PNG

• how to save h264 stream into .264 file

  6 mars 2015, par user3547405

  I’m using nginx-rtmp-module build hls server, when I play it on safari, it does not shows image,then i use this command ffmpeg -i rtmp://192.168.4.213/hls/testH264 -c copy -map 0 -f segment -segment_list playlist.m3u8 -segment_time 5 output%03d.ts, it shows missing picture in access unit with size 28184,so i think maybe the raw h264 stream has some problem,then i directly save the h264 stream into .264 file,but when i play the .264 file with vlc,the screen is fuzzy,help