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• avcodec/videotoolboxenc : allow low latency RC with HEVC

  6 septembre, par Cameron Gutman

  avcodec/videotoolboxenc : allow low latency RC with HEVC
  It is supported only for H.264 on Intel Macs, but it can be used with
  
  both H.264 and HEVC on Apple Silicon.
  Signed-off-by : Cameron Gutman <aicommander@gmail.com>
  

  • [DH] libavcodec/videotoolboxenc.c

• Some Queries on HLS Independent Segments and AAC codec ?

  1er mars 2023, par muraliv

  According to Apple HLS spec, #EXT-X-INDEPENDENT-SEGMENTS tag indicates that the segments are independent and can be decoded indepedently of each other. This tag can be specified either in master playlist or rendition playlist or both.

  


  I assume that this applies for both video and audio decoding ? If so, if I used MediaConvert or ffmpeg to prepare a HLS stream with AAC-LC codec, then audio for each HLS segements can be decoded independently ? I read somewhere that AAC requires 2 packets/frames for decoding due to its overlapping encoding logic. Then, will the first audio packet for the next HLS segment depend on the last audio packet of the previous HLS segment for decoding, or is it still the case that the audio packets can be decoded independently across HLS segments ?

  


• Why does my webm not work in Unity but others do ?

  5 avril 2019, par UserDude

  Ok Im just trying to play a transparent video in Unity and Im following http://mikebrinkerink.com/2018/04/05/preparing-a-video-with-alpha-channel-for-unity/ and other tutorials.

  Ive tried exporting as ProRes 444 with alpha and as Webm VP8, and using terminal ffmpeg commands. Yet when I drop the video into Unity it loads indefinitely and I have to force quit.

  My file is this : https://drive.google.com/file/d/1RhOvYfeaK1rEaKdlTNcJB9EBpz4xxjvw/view?usp=sharing

  And this one that I downloaded works fine : https://simpl.info/videoalpha/video/dancer1.webm

  Whats the difference/how can I get mine to work ?

  Log :

  ffmpeg -i my_clip_with_alpha.avi -vcodec vp8 -acodec libvorbis -pix_fmt yuva420p -metadata:s:v:0 alpha_mode=”1″ -auto-alt-ref 0 my_vp8_clip_with_alpha.webm​

  as the command (with my clip’s name)

  Then

  built with Apple LLVM version 10.0.0 (clang-1000.11.45.5)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/4.1.2 --enable-shared --enable-pthreads --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags='-I/Library/Java/JavaVirtualMachines/openjdk-11.0.2.jdk/Contents/Home/include -I/Library/Java/JavaVirtualMachines/openjdk-11.0.2.jdk/Contents/Home/include/darwin' --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libmp3lame --enable-libopus --enable-librubberband --enable-libsnappy --enable-libtesseract --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp --enable-libspeex --enable-videotoolbox --disable-libjack --disable-indev=jack --enable-libaom --enable-libsoxr
  
    libavutil      56. 22.100 / 56. 22.100
  
    libavcodec     58. 35.100 / 58. 35.100
  
    libavformat    58. 20.100 / 58. 20.100
  
    libavdevice    58.  5.100 / 58.  5.100
  
    libavfilter     7. 40.101 /  7. 40.101
  
    libavresample   4.  0.  0 /  4.  0.  0
  
    libswscale      5.  3.100 /  5.  3.100
  
    libswresample   3.  3.100 /  3.  3.100
  
    libpostproc    55.  3.100 / 55.  3.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/Users/skylarthomas/Desktop/INSTRUCTIONS1_00000.mov':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 537199360
  
      compatible_brands: qt  
  
      creation_time   : 2019-03-27T00:19:30.000000Z
  
    Duration: 00:00:17.05, start: 0.000000, bitrate: 40959 kb/s
  
      Stream #0:0(eng): Video: prores (ap4h / 0x68347061), yuva444p10le(tv, bt709, progressive), 2215x1773, 40467 kb/s, SAR 1:1 DAR 2215:1773, 29.97 fps, 29.97 tbr, 30k tbn, 30k tbc (default)
  
      Metadata:
  
        creation_time   : 2019-03-27T00:19:30.000000Z
  
        handler_name    : Apple Video Media Handler
  
        encoder         : Apple ProRes 4444
  
        timecode        : 00:00:00:00
  
      Stream #0:1(eng): Data: none (tmcd / 0x64636D74), 0 kb/s (default)
  
      Metadata:
  
        creation_time   : 2019-03-27T00:19:30.000000Z
  
        handler_name    : Time Code Media Handler
  
        timecode        : 00:00:00:00
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (prores (native) -> vp8 (libvpx))
  
  Press [q] to stop, [?] for help
  
  [libvpx @ 0x7fe11701d600] v1.8.0
  
  Output #0, webm, to 'my_vp8_clip_with_alpha.webm':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 537199360
  
      compatible_brands: qt  
  
      encoder         : Lavf58.20.100
  
      Stream #0:0(eng): Video: vp8 (libvpx), yuva420p, 2215x1773 [SAR 1:1 DAR 2215:1773], q=-1--1, 200 kb/s, 29.97 fps, 1k tbn, 29.97 tbc (default)
  
      Metadata:
  
        creation_time   : 2019-03-27T00:19:30.000000Z
  
        handler_name    : Apple Video Media Handler
  
        timecode        : 00:00:00:00
  
        alpha_mode      : ”1″
  
        encoder         : Lavc58.35.100 libvpx
  
      Side data:
  
        cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
  
  frame=    2 fps=2.0 q=0.0 size=       1kB time=00:00:00.03 bitrate= 200.7kbits/sframe=    6 fps=3.7 q=0.0 size=       1kB time=00:00:00.16 bitrate=  40.6kbits/sframe=   10 fps=4.5 q=0.0 size=       1kB time=00:00:00.30 bitrate=  22.7kbits/s speedframe=   35 fps=2.9 q=0.0 size=       1kB time=00:00:01.13 bitrate=   6.0kbits/s speed=0.0934x