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• avcodec/get_buffer : Don't get AVPixFmtDescriptor unnecessarily

  15 août 2022, par Andreas Rheinhardt

  avcodec/get_buffer : Don't get AVPixFmtDescriptor unnecessarily
  It is unused since 3575a495f6dcc395656343380e13c57d48b9f976
  
  (and the error message is dangerous : av_get_pix_fmt_name(format)
  
  returns NULL iff av_pix_fmt_desc_get(format) returns NULL
  
  and using a NULL string for %s would be UB).
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavcodec/get_buffer.c

• avcodec/smcenc : Move PutByteContext to stack

  19 novembre 2021, par Andreas Rheinhardt

  avcodec/smcenc : Move PutByteContext to stack
  This context is transient, so putting it on the stack is more natural.
  
  Also reduces codesize : 24E6->2296 B with GCC 10 and -O3.
  Reviewed-by : Paul B Mahol <onemda@gmail.com>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavcodec/smcenc.c

• Fragmented mp4 file is not played by MSE

  19 mai 2020, par Daniel

  I created a fragmented mp4 file with ffmpeg (from h264), and removed the first 6 moof and mdat pairs.

  



  So now it still has the correct order of boxes : ftyp, moov, moof, mdat, moof, mdat, ..., but the first moof packet has the sequenceNumber of 7.

  



  VLC can play it fine, 'Movies & TV' can also play, but the first some seconds are black.

  



  If I drag the file into the browser, it can also play it fine.

  



  It is however not being displayed at all in the browser (Chrome) if I feed it via MSE.

  



  No error messages are printed, and in the media-internals' log it can be seen that the videoplayer starts playing in the first second and suspends it only in the 18th second :

  



  Timestamp   Property    Value
00:00:00.000    origin_url  "https://localhost:8443/"
00:00:00.000    kFrameUrl   "https://localhost:8443/websocket/videodemo.html"
00:00:00.000    kFrameTitle "WebSocket and MSE demo"
00:00:00.000    url "blob:https://localhost:8443/3b4d4b1a-7c08-4136-95fe-dabc14fba95f"
00:00:00.000    info    "ChunkDemuxer"
00:00:00.000    pipeline_state  "kStarting"
00:00:01.067    kVideoTracks    [{"alpha mode":"is_opaque","codec":"h264","coded size":"1600x900","color space":"{primaries:BT709, transfer:BT709, matrix:BT709, range:LIMITED}","encryption scheme":"Unencrypted","flipped":false,"has_extra_data":false,"natural size":"1600x900","profile":"h264 main","rotation":"0°","visible rect":"0,0 1600x900"}]
00:00:01.067    debug   "Video rendering in low delay mode."
00:00:01.070    info    "Using D3D11 device for DXVA"
00:00:01.075    kIsVideoDecryptingDemuxerStream false
00:00:01.075    kVideoDecoderName   "MojoVideoDecoder"
00:00:01.075    kIsPlatformVideoDecoder true
00:00:01.075    info    "Selected MojoVideoDecoder for video decoding, config: codec: h264, profile: h264 main, alpha_mode: is_opaque, coded size: [1600,900], visible rect: [0,0,1600,900], natural size: [1600,900], has extra data: false, encryption scheme: Unencrypted, rotation: 0°, flipped: 0, color space: {primaries:BT709, transfer:BT709, matrix:BT709, range:LIMITED}"
00:00:01.075    pipeline_state  "kPlaying"
00:00:01.067    duration    "unknown"
00:00:18.926    pipeline_state  "kSuspending"
00:00:18.926    pipeline_state  "kSuspended"
00:00:18.927    event   "SUSPENDED"


  



  Here is the video file for reference.

  



  What is the problem with this file, why is it not displayed in the browser with MSE ?