Recherche avancée

Sur d’autres sites (7632)

• H264 encoder settings

  30 novembre 2011, par Chris Robinson

  I'm using xuggler to encode a series of images to an MP4 file. I use the following code to setup the IStreamCoder and specify the H264 codec :

  // only set if codec is H264
  
  Configuration.configure("/usr/local/xuggler/share/ffmpeg/libx264-hq.ffpreset",
  
              outStreamCoder);
  
  
  
  outStreamCoder.setNumPicturesInGroupOfPictures(12);
  
  outStreamCoder.setCodec(codec);
  
  outStreamCoder.setBitRate(videoSettings.getBitrate());
  
  outStreamCoder.setBitRateTolerance(videoSettings.getBitrateTolerance());
  
  outStreamCoder.setPixelType(IPixelFormat.Type.YUV420P);
  
  outStreamCoder.setHeight(videoSettings.getResolution().height);
  
  outStreamCoder.setWidth(videoSettings.getResolution().width);
  
  outStreamCoder.setFlag(IStreamCoder.Flags.FLAG_QSCALE, true);
  
  outStreamCoder.setGlobalQuality(0);
  
  fps = IRational.make((int) videoSettings.getFramerate(), 1);
  
  outStreamCoder.setFrameRate(fps);
  
  outStreamCoder.setTimeBase(IRational.make(fps.getDenominator(), fps.getNumerator()));

  which yields the following output :

  Codec: CODEC_ID_H264
  
  Resolution: 1280x720
  
  Bitrate: 25000
  
  Bitrate Tolerance: 1000
  
  Framerate: 25.0

  

  Now when I specify the MPEG4 codec, I get the following output :

  Codec: CODEC_ID_MPEG4
  
  Resolution: 1280x720
  
  Bitrate: 25000
  
  Bitrate Tolerance: 1000
  
  Framerate: 25.0

  

  As you can see, the only difference is the ICodec type (MPEG4 instead of H264) and the use of the preset (which is required by xuggler when using an H264 codec). Can anyone explain to me the huge difference in quality and tell me how to resolve the issue ?

• avcodec/aom_film_grain : implement AFGS1 parsing

  26 février 2024, par Niklas Haas

  avcodec/aom_film_grain : implement AFGS1 parsing
  Based on the AOMedia Film Grain Synthesis 1 (AFGS1) spec :
  
    https://aomediacodec.github.io/afgs1-spec/
  The parsing has been changed substantially relative to the AV1 film
  
  grain OBU. In particular :
  1. There is the possibility of maintaining multiple independent film
  
     grain parameter sets, and decoders/players are recommended to pick
  
     the one most appropriate for the intended display resolution. This
  
     could also be used to e.g. switch between different grain profiles
  
     without having to re-signal the appropriate coefficients.
  2. Supporting this, it's possible to *predict* the grain coefficients
  
     from previously signalled parameter sets, transmitting only the
  
     residual.
  3. When not predicting, the parameter sets are now stored as a series of
  
     increments, rather than being directly transmitted.
  4. There are several new AFGS1-exclusive fields.
  I placed this parser in its own file, rather than h2645_sei.c, since
  
  nothing in the generic AFGS1 film grain payload is specific to T.35, and
  
  to compartmentalize the code base.
  

  • [DH] libavcodec/aom_film_grain.c
  • [DH] libavcodec/aom_film_grain.h

• path issues with FFMPEG Bash script to concat and encode across multiple subfolders

  27 décembre 2022, par NoobCoder

  I'm trying to write a bash script for Mac OSx Terminal to compress a series of GoPro .MP4 videos from the SDcard directly into a smaller .MP4s on a local network server. The GoPro saves .MP4s in the 100GOPRO folder on the card. After filming, I will through that folder and manually put .MP4s from each game into subfolders within the 100GOPRO folder, named A1, A2, A3, etc.

  


  Folder structure

  


  /GoPro/DCIM/100GOPRO/
               -------/A1/
                       -----GX01xxx1.mp4
                       -----GX01xxx2.mp4
               -------/A2/
                       -----GX01xxx3.mp4
                       -----GX01xxx4.mp4
                       -----GX01xxx5.mp4
                       -----GX01xxx6.mp4


  


  ...etc

  


  I would like then like to run a script from the 100GOPRO folder that will do these steps :

  


  

  1. Within each subfolder, auto-create a file.txt with the names of the subfolder's .MP4s in the format to concat the files (each line has "file 'GX01xxx3.mp4'")

  


  2. Pass that subfolder's file.txt as the input to ffmpeg to reencode and save to a network folder with the name A1.mp4 or A2.mp4

  


  3. Repeat for each subfolder and quit.

  


  


  I'm getting hung up on the dynamic path to the subfolder's file.txt. My code just creates a file.txt in the 100GOPRO folder, and appends all the subfolder contents into that single long combined text file. The output then would create a correct first MP4, but second MP4 contains folder 1 and 2, then 3 contains 1, 2, and 3, etc.

  


  Here's the script I ran :

  


  #!/bin/bash
for f in A*/*.mp4 ; do
echo file \'$f\' >> list.txt ;
done && ffmpeg -f concat -safe 0 -i list.txt /Volume/Server/Videos/A$f.mp4 && rm list.txt


  


  Clearly, failing in how that path for echo to save in the subfolder A*, how to call that subfolder's file.txt as the input for ffmpeg, and how to name the output after the folder.

  


  Thanks for any help you can offer.