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• FFMPEG (Input 8K AAC -> (AAC FLV) youtube streaming noise

  17 septembre 2017, par Biswa Das

  Hello I run a streaming encoder for a non profit cause. Chosen FFMPEG as it’s very simple and doing the job near perfectly however the audio is noisy popping and cracking. Video is crystal clear.

  ffmpeg version N-86950-g1bef008 Copyright (c) 2000-2017 the FFmpeg developers
  built with gcc 7.1.0 (GCC)

  Here is my command.

  ffmpeg -rtsp_transport tcp -i $RTSP_SRC -vcodec copy -af "volume=12dB" -ar 8000 -acodec aac -f flv rtmp://a.rtmp.youtube.com/live2/$DEST_KEY

  However when I just play the stream the noise levels are quite acceptable.

  ffplay -rtsp_transport tcp -i $RTSP_SRC

  What I have tried so far.

  • Change input audio sampling from 8K to 16K (that’s all is supported currently). It made the noise problem much worse. I can’t change it to a native FLV sampling(44100 or 22050 or 11025) at least not yet, the integrated rtsp stream does not support it.)
  • My working theory is during resampling stream noise is getting boosted. So to eliminate that I tried audio copy codec even then there is no significant improvement.

• ffmpeg : Split MP3 in 1 second chunks fast ?

  30 décembre 2019, par Niko

  I want to split mp3 into one second chunks fast. I have the mp3 already in memory (in crystal lang) and want to process it further (so I need it in memory after splitting). I got two possiblities working :

  • Saving the file to ram disk, calling ffmpeg -segment on it, reading all the segement files into memory.
  • Piping the file into ffprobe --show_frames and parsing the pkt_pos fields from the result.

  Both are slow about one second due to unnescessary overhead. Writing to disk and reading hundrets of files in the first case, outputting a lot of unneeded information about a lot of unneeded frames in the second.

  I see two possibilities to improve :

  • a custom filter for ffmpeg that outputs the segements with a separator to stdout.
  • a custom filter for ffprobe similar to --show_frames but with a framestep parameter (the existing framestep filter only seems to work with video files) which outputs only the byte offset of the frames.

  Perhaps I’m missing possibilites with the existing filters. Perhaps there is a tool better fitted for my needs than ffmpeg. I’d be happy for any hints.

• avcodec/mediacodecdec : add workaround for buggy amlogic mpeg2 decoder

  26 avril 2018, par Aman Gupta

  avcodec/mediacodecdec : add workaround for buggy amlogic mpeg2 decoder
  I tested the previous mediacodec changes on seven different Android
  
  TV devices, with both mpeg2 and h264 content. All except one worked
  
  as expected. The exception was the MiBox3 running Android 6.0.1,
  
  where playback would freeze on a frame every few seconds. I tested
  
  two other AMLogic devices with newer Android versions that did not
  
  show the same problem. H264 decoding on the MiBox3 was also not affected,
  
  so this workaround applies only to OMX.amlogic.mpeg2.decoder.awesome
  
  on Android API22.
  There is a rumor that Xiaomi is planning to release Android Oreo for
  
  the MiBox3, so I will revisit in a few months to confirm whether this
  
  is specific to os/driver version or the chipset used in that device.
  Signed-off-by : Aman Gupta <aman@tmm1.net>
  
  Signed-off-by : Matthieu Bouron <matthieu.bouron@gmail.com>
  

  • [DH] libavcodec/mediacodecdec.c