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• avcodec/omx : Fix handling of fragmented buffers

  17 janvier 2019, par Dave Stevenson

  avcodec/omx : Fix handling of fragmented buffers
  See https://trac.ffmpeg.org/ticket/7687
  If an encoded frame is returned split over two or more
  
  IL buffers due to the size, then there is a race between
  
  whether get_buffer will fail, return NULL, and a truncated
  
  frame is passed on, or IL will return the remaining part
  
  of the encoded frame.
  
  If get_buffer returns NULL, part of the frame is left behind
  
  in the codec, and will be collected on the next call. That
  
  then leaves a frame stuck in the codec. Repeat enough times
  
  and the codec FIFO is full, and the pipeline stalls.
  A performance improvement in the Raspberry Pi firmware means
  
  that the timing has changed, and now frequently drops into the
  
  case where get_buffer returns NULL.
  Add code such that should a buffer be received without
  
  OMX_BUFFERFLAG_ENDOFFRAME that get_buffer is called with wait
  
  set, so we wait for the remainder of the frame.
  
  This code has been made conditional on the Pi build in case
  
  other IL implementations don't handle ENDOFFRAME correctly.
  Signed-off-by : Dave Stevenson <dave.stevenson@raspberrypi.org>
  
  Signed-off-by : Aman Gupta <aman@tmm1.net>
  
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DH] libavcodec/omx.c

• using pocketsphinx_continuous with a .wav file

  3 avril 2013, par user2242131

  I am attempting to write an application that will allow a user to speak a small set of commands from a remote system and have them executed on my server. Using pocketsphinx to parse the spoken text. When run locally with the microphone, pocketsphinx_continuous works perfectly no matter how I slur the words. But when importing the audio file and using ffmpeg to downsample the audio to a single channel, 16 bit PCM file, it will parse the first word without difficulty. Then it will skip everything else and treat it as . I am confident that the problem is in the file format and not in the pocketsphinx configuration.

  Using command line
  ffmpeg -y -i Sound\AddSheet.wav -ac 1 -f s16le -acodec pcm_s16le -ar 16k AddTmp.wav
  in a batch file.

  The bottom of the output I get is :

  INFO: fsg_search.c(1407): Start node ADD.0:5:47
  
  INFO: fsg_search.c(1407): Start node <sil>.0:2:49
  
  INFO: fsg_search.c(1446): End node <sil>.126:128:305 (-486)
  
  INFO: fsg_search.c(1662): lattice start node <s>.0 end node <sil>.126
  
  INFO: ps_lattice.c(1352): Normalizer P(O) = alpha(<sil>:126:305) = -175371
  
  INFO: ps_lattice.c(1390): Joint P(O,S) = -176076 P(S|O) = -705
  
  000000000: ADD USER
  
  </sil></sil></s></sil></sil>

  Which is not the audio in the file. The words spoken in the file are "ADD SPREADSHEET", which works perfectly from the same microphone without the intervening .wav file.

  I have tried increasing the audio volume and decreasing the background noise using sox :

  sox -v 3.0 Sound\%1 Sound\%1-loud.wav ffmpeg -i Sound\%1-loud.wav -vn -ss 00:00:00 -t 00:00:01 -y Sound\%1-noiseaud.wav 
  
  sox Sound\%1-noiseaud.wav -n noiseprof Sound\%1-noise.prof 
  
  sox Sound\%1 Sound\%1-clean.wav noisered sound\noise.prof 0.21 
  
  ffmpeg -y -i Sound\%1-clean.wav -ac 1 -f s16le -acodec pcm_s16le -ar 16k AddTmp.wav

  with no noticeable effect on the final results.

  If you look at the output you will notice that fsg_search.c has found ADD as the start node, then silence for the remainder. Please help on this.

• How to use sunlubo/SwiftFFmpeg library in iOS swift ?

  29 mars 2022, par Ankur Pachauri

  I am trying to use https://github.com/sunlubo/SwiftFFmpeg library in iOS to convert mp4 file to mpegts. But I am getting below error when trying to add it using SPM :

  


  

  


  & No such module 'CFFmpeg' error when trying to add the library manually as used in the Demo project(https://github.com/sunlubo/SwiftFFmpegDemo-iOS). Can anyone provide me the steps or example on how to use this library for iOS ?

  


  I am using a M1 Macbook, Xcode 13, SwiftFFmpeg library version(1.0.5), Swift version(5.4)

  


  Thanks in advance !