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• Gstreamer AAC encoding no more supported ?

  22 juillet 2016, par Gianks

  i’d like to include AAC as one of the compatible formats in my app but i’m having troubles with its encoding.
  FAAC seems to be missing in GStreamer-1.0 Debian-derived packages (see Ubuntu) and the main reason for that (if i got it correctly) is the presence of avenc_aac (Lunchpad bugreport) as a replacement.

  I’ve tried the following :

  gst-launch-1.0 filesrc location="src.avi" ! tee name=t  t.! queue ! decodebin ! progressreport ! x264enc ! mux. t.! queue ! decodebin ! audioconvert ! audioresample ! avenc_aac compliance=-2 ! mux. avmux_mpegts name=mux ! filesink location=/tmp/test.avi

  It hangs prerolling with :

  ERROR libav :0:: AAC bitstream not in ADTS format and extradata missing

  Using mpegtsmux instead of avmux_mpegts seems to work since the file is created but it results with no working audio (with some players it’s completely unplayable).

  This is the trace of mplayer :

  Opening audio decoder: [ffmpeg] FFmpeg/libavcodec audio decoders
  
  [aac @ 0x7f2860d6c3c0]channel element 3.15 is not allocated
  
  [aac @ 0x7f2860d6c3c0]Sample rate index in program config element does not match the sample rate index configured by the container.
  
  [aac @ 0x7f2860d6c3c0]Inconsistent channel configuration.
  
  [aac @ 0x7f2860d6c3c0]get_buffer() failed
  
  [aac @ 0x7f2860d6c3c0]Assuming an incorrectly encoded 7.1 channel layout instead of a spec-compliant 7.1(wide) layout, use -strict 1 to decode according to the specification instead.
  
  [aac @ 0x7f2860d6c3c0]Reserved bit set.
  
  [aac @ 0x7f2860d6c3c0]Number of bands (20) exceeds limit (14).
  
  [aac @ 0x7f2860d6c3c0]invalid band type
  
  [aac @ 0x7f2860d6c3c0]More than one AAC RDB per ADTS frame is not implemented. Update your FFmpeg version to the newest one from Git. If the problem still occurs, it means that your file has a feature which has not been implemented.
  
  [aac @ 0x7f2860d6c3c0]Reserved bit set.
  
  [aac @ 0x7f2860d6c3c0]Number of bands (45) exceeds limit (28).
  
  Unknown/missing audio format -> no sound
  
  ADecoder init failed :(
  
  Opening audio decoder: [faad] AAC (MPEG2/4 Advanced Audio Coding)
  
  FAAD: compressed input bitrate missing, assuming 128kbit/s!
  
  AUDIO: 44100 Hz, 2 ch, floatle, 128.0 kbit/9.07% (ratio: 16000->176400)
  
  Selected audio codec: [faad] afm: faad (FAAD AAC (MPEG-2/MPEG-4 Audio))
  
  ==========================================================================
  
  AO: [pulse] 44100Hz 2ch floatle (4 bytes per sample)
  
  Starting playback...
  
  FAAD: error: Bitstream value not allowed by specification, trying to resync!
  
  FAAD: error: Invalid number of channels, trying to resync!
  
  FAAD: error: Invalid number of channels, trying to resync!
  
  FAAD: error: Bitstream value not allowed by specification, trying to resync!
  
  FAAD: error: Invalid number of channels, trying to resync!
  
  FAAD: error: Bitstream value not allowed by specification, trying to resync!
  
  FAAD: error: Channel coupling not yet implemented, trying to resync!
  
  FAAD: error: Invalid number of channels, trying to resync!
  
  FAAD: error: Invalid number of channels, trying to resync!
  
  FAAD: error: Bitstream value not allowed by specification, trying to resync!
  
  FAAD: Failed to decode frame: Bitstream value not allowed by specification 
  
  Movie-Aspect is 1.33:1 - prescaling to correct movie aspect.
  
  VO: [vdpau] 640x480 => 640x480 Planar YV12 
  
  A:3602.2 V:3600.0 A-V:  2.143 ct:  0.000   3/  3 ??% ??% ??,?% 0 0 
  
  FAAD: error: Array index out of range, trying to resync!
  
  FAAD: error: Bitstream value not allowed by specification, trying to resync!
  
  FAAD: error: Bitstream value not allowed by specification, trying to resync!
  
  FAAD: error: Unexpected fill element with SBR data, trying to resync!
  
  FAAD: error: Bitstream value not allowed by specification, trying to resync!
  
  FAAD: error: Bitstream value not allowed by specification, trying to resync!
  
  FAAD: error: Channel coupling not yet implemented, trying to resync!
  
  FAAD: error: Invalid number of channels, trying to resync!
  
  FAAD: error: PCE shall be the first element in a frame, trying to resync!
  
  FAAD: error: Invalid number of channels, trying to resync!
  
  FAAD: Failed to decode frame: Invalid number of channels 
  
  A:3602.2 V:3600.1 A-V:  2.063 ct:  0.000   4/  4 ??% ??% ??,?% 0 0 

  These the messages produced by VLC (10 seconds of playback) :

  ts info: MPEG-4 descriptor not found for pid 0x42 type 0xf
  
  core error: option sub-original-fps does not exist
  
  subtitle warning: failed to recognize subtitle type
  
  core error: no suitable demux module for `file/subtitle:///tmp//test.avi.idx'
  
  avcodec info: Using NVIDIA VDPAU Driver Shared Library 361.42 Tue Mar 22 17:29:16 PDT 2016 for hardware decoding.
  
  core warning: VoutDisplayEvent 'pictures invalid'
  
  core warning: VoutDisplayEvent 'pictures invalid'
  
  packetizer_mpeg4audio warning: Invalid ADTS header
  
  packetizer_mpeg4audio warning: ADTS CRC not supported
  
  packetizer_mpeg4audio warning: Invalid ADTS header
  
  packetizer_mpeg4audio error: Multiple blocks per frame in ADTS not supported
  
  packetizer_mpeg4audio warning: Invalid ADTS header
  
  packetizer_mpeg4audio error: Multiple blocks per frame in ADTS not supported
  
  packetizer_mpeg4audio warning: ADTS CRC not supported
  
  packetizer_mpeg4audio error: Multiple blocks per frame in ADTS not supported
  
  packetizer_mpeg4audio error: Multiple blocks per frame in ADTS not supported
  
  packetizer_mpeg4audio error: Multiple blocks per frame in ADTS not supported
  
  packetizer_mpeg4audio error: Multiple blocks per frame in ADTS not supported
  
  packetizer_mpeg4audio error: Multiple blocks per frame in ADTS not supported
  
  packetizer_mpeg4audio error: Multiple blocks per frame in ADTS not supported
  
  packetizer_mpeg4audio error: Multiple blocks per frame in ADTS not supported
  
  packetizer_mpeg4audio error: Multiple blocks per frame in ADTS not supported
  
  packetizer_mpeg4audio warning: Invalid ADTS header
  
  packetizer_mpeg4audio error: Multiple blocks per frame in ADTS not supported
  
  packetizer_mpeg4audio warning: Invalid ADTS header
  
  packetizer_mpeg4audio warning: Invalid ADTS header
  
  packetizer_mpeg4audio error: Multiple blocks per frame in ADTS not supported
  
  packetizer_mpeg4audio warning: Invalid ADTS header
  
  packetizer_mpeg4audio warning: Invalid ADTS header
  
  packetizer_mpeg4audio warning: Invalid ADTS header
  
  packetizer_mpeg4audio error: Multiple blocks per frame in ADTS not supported
  
  packetizer_mpeg4audio warning: Invalid ADTS header
  
  packetizer_mpeg4audio warning: Invalid ADTS header
  
  packetizer_mpeg4audio error: Multiple blocks per frame in ADTS not supported
  
  packetizer_mpeg4audio warning: Invalid ADTS header
  
  packetizer_mpeg4audio error: Multiple blocks per frame in ADTS not supported
  
  packetizer_mpeg4audio error: Multiple blocks per frame in ADTS not supported
  
  packetizer_mpeg4audio error: Multiple blocks per frame in ADTS not supported
  
  packetizer_mpeg4audio error: Multiple blocks per frame in ADTS not supported
  
  packetizer_mpeg4audio error: Multiple blocks per frame in ADTS not supported
  
  packetizer_mpeg4audio error: Multiple blocks per frame in ADTS not supported
  
  packetizer_mpeg4audio warning: Invalid ADTS header
  
  packetizer_mpeg4audio error: Multiple blocks per frame in ADTS not supported
  
  packetizer_mpeg4audio error: Multiple blocks per frame in ADTS not supported
  
  packetizer_mpeg4audio error: Multiple blocks per frame in ADTS not supported
  
  packetizer_mpeg4audio error: Multiple blocks per frame in ADTS not supported
  
  packetizer_mpeg4audio error: Multiple blocks per frame in ADTS not supported
  
  packetizer_mpeg4audio error: Multiple blocks per frame in ADTS not supported
  
  packetizer_mpeg4audio error: Multiple blocks per frame in ADTS not supported

  Using the error of the hanging pipeline I’ve finally discovered that avenc_aac should be told in such way to output the data NOT in RAW AAC but in ADTS AAC, the point is that i’ve no idea how to do that with Gstreamer. See here, bottom of the page : FFMPEG Ticket

  At this point since i’ve found no documentation seems right to say we have no support for AAC encoding in GStreamer... which isn’t true, i guess ! (IMHO anyway seems strange the missing of FAAC if AVENC_AAC requires all the time to be set in experimental mode)

  Can someone propose a working pipeline for this ?

  UPDATE

  After some more research i’ve found (via gst-inspect on avenc_aac) what i’m probably looking for but i don’t know how to setup it as needed.
  Have a look at stream-format :

  Pad Templates:
  
    SRC template: 'src'
  
      Availability: Always
  
      Capabilities:
  
        audio/mpeg
  
                 channels: [ 1, 6 ]
  
                     rate: [ 4000, 96000 ]
  
              mpegversion: 4
  
            stream-format: raw
  
          base-profile: lc

  Thanks

• Compiler Optimization flags for ffmpeg on Intel Xeon Phi

  10 octobre 2016, par Ambujam

  I am trying to compile ffmpeg on Xeon Phi processor. Are there any specific compiler optimization flags specific for Xeon Phi that I can enable while configuring ffmpeg so that I can achieve better performance in terms of encoder frames per second ?

  Encoder used : x264
  Operating System : CentOS 7.2
  Compiler : GCC 4.8.5

  Currently, I am configuring ffmpeg with the below command line :

  ./configure --prefix="$HOME/ffmpeg_build" 
  
  --extra-cflags="-I$HOME/ffmpeg_build/include" 
  
  --extra-ldflags="-L$HOME/ffmpeg_build/lib" --bindir="$HOME/bin" 
  
  --pkg-config-flags="--static" --enable-gpl --enable-nonfree 
  
  --enable-libx264

• FFMPEG encoding with Intel Quick Sync, throwing "Access violation reading location "

  22 octobre 2015, par Paul Knopf

  I am using FFMPEG ffmpeg-20150610-git-913685f, from here.

  Using this library, I setup a application that captures UYVY frames from my frame grabber and encodes/muxes them to an MP4 file, using libx264. Works without issues.

  Now, I wanted to try to enabling Intel Quick Sync, so I changed the encoder.

  // old (libx264)
  
  //AVCodec* codec = avcodec_find_encoder(AV_CODEC_ID_H264);
  
  // new (Intel Quick Sync)
  
  AVCodec* codec = avcodec_find_encoder_by_name("h264_qsv");

  It finds the encoder ok. However, at the time of encoding a frame, I get the following exception.

  Unhandled exception at 0x000000005D4DDC9E (avcodec-56.dll) in
  MedXChangeDecLinkTest.exe : 0xC0000005 : Access violation reading
  location 0x0000000000000048.

  The exact API call is :

  avcodec_encode_video2(_internals->videoStream.stream->codec, &pkt, _internals->videoStream.frame, &got_packet);

  Is there more I need to do ? I noticed that there was a commit that added some additional pixel formats for QSV here. Do I have to do something differently, compared to how things were done with libx264 ?

  UPDATE : I also just realized that I am getting an error on the stdout.

  [h264_qsv @ 000000c7e6d8e680] Specified pixel format yuv420p is invalid or not supported