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• avcodec/mediacodecdec : warn when input buffers are not configured with proper size

  5 septembre 2019, par Aman Gupta

  avcodec/mediacodecdec : warn when input buffers are not configured with proper size
  In rare circumstances, if the codec is not configured with the
  
  proper parameters the input buffers can be allocated with a size
  
  that's too small to hold an individual packet. Since MediaCodec
  
  expects exactly one incoming buffer with a given PTS, it is not
  
  valid to split data for a given PTS across two input buffers.
  See https://developer.android.com/reference/android/media/MediaCodec#data-processing:
    > Do not submit multiple input buffers with the same timestamp
  Signed-off-by : Aman Gupta <aman@tmm1.net>
  

  • [DH] libavcodec/mediacodecdec.c

• fftools/ffmpeg_dec : abort if avcodec_send_packet() returns EAGAIN

  22 mai 2023, par James Almer

  fftools/ffmpeg_dec : abort if avcodec_send_packet() returns EAGAIN
  As the comment in the code mentions, EAGAIN is not an expected value here
  
  because we call avcodec_receive_frame() until all frames have been returned.
  
  avcodec_send_packet() returning EAGAIN means a packet is still buffered, which
  
  hints that the underlying decoder is buggy and not fetching packets as it
  
  should.
  An example of this behavior was in the libdav1d wrapper before f209614290,
  
  where feeding it split frames (or individual OBUs) would result in the CLI
  
  eventually printing the confusing "Error submitting packet to decoder : Resource
  
  temporarily unavailable" error message, and just keep going until EOF without
  
  returning new frames.
  Signed-off-by : James Almer <jamrial@gmail.com>
  

  • [DH] fftools/ffmpeg_dec.c

• How to convert from AV_PIX_FMT_BGRA to PIX_FMT_PAL8 ?

  29 juillet 2014, par Jona

  I’m having a hard time converting my images from AV_PIX_FMT_BGRA to PIX_FMT_PAL8. Unfortunately sws_getCachedContext doesn’t support the conversion to PIX_FMT_PAL8.

  What I’m trying to do is convert my images into a GIF video with higher quality output. It seems that PIX_FMT_PAL8 could potentially provide the higher quality output I’m looking for.

  According to this documentation I need to palettize the pixel data, but I have no clue how to do that.

  When the pixel format is palettized RGB (PIX_FMT_PAL8), the palettized
  image data is stored in AVFrame.data[0]. The palette is transported in
  AVFrame.data[1], is 1024 bytes long (256 4-byte entries) and is
  formatted the same as in PIX_FMT_RGB32 described above (i.e., it is
  also endian-specific). Note also that the individual RGB palette
  components stored in AVFrame.data[1] should be in the range 0..255.
  This is important as many custom PAL8 video codecs that were designed
  to run on the IBM VGA graphics adapter use 6-bit palette components.

  Any help or direction would be appreciated.