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• avcodec/executor: remove unused ready callback

  24 September 2024, by Nuo Mi

  avcodec/executor: remove unused ready callback
  Due to the nature of multithreading, using a "ready check" mechanism may introduce a deadlock. For example:
  Suppose all tasks have been submitted to the executor, and the last thread checks the entire list and finds
  
  no ready tasks. It then goes to sleep, waiting for a new task. However, for some multithreading-related reason,
  
  a task becomes ready after the check. Since no other thread is aware of this and no new tasks are being added to
  
  the executor, a deadlock occurs.
  In VVC, this function is unnecessary because we use a scoreboard. All tasks submitted to the executor are ready tasks.
  

  • [DH] libavcodec/executor.c
  • [DH] libavcodec/executor.h
  • [DH] libavcodec/vvc/thread.c

• lavc/aarch64/fdct: add neon-optimized fdct for aarch64

  17 April 2024, by Ramiro Polla

  lavc/aarch64/fdct: add neon-optimized fdct for aarch64
  The code is imported from libjpeg-turbo-3.0.1. The neon registers used
  
  have been changed to avoid modifying v8-v15.
  Reviewed-by: Martin Storsjö <martin@martin.st>
  

  • [DH] libavcodec/aarch64/Makefile
  • [DH] libavcodec/aarch64/fdct.h
  • [DH] libavcodec/aarch64/fdctdsp_init_aarch64.c
  • [DH] libavcodec/aarch64/fdctdsp_neon.S
  • [DH] libavcodec/avcodec.h
  • [DH] libavcodec/fdctdsp.c
  • [DH] libavcodec/fdctdsp.h
  • [DH] libavcodec/options_table.h
  • [DH] libavcodec/tests/aarch64/dct.c

• iOS Objective C Opus audio stream kAudioFormatOpus — specification / conversion query

  16 April 2022, by deffodeffo

  I'm working on a React Native voice app wanting to record straight to an Opus stream.

  


  On the iOS side at device level, I'm working in Objective C and I'm using an AVAudioSession recorder with formatID set to kAudioFormatOpus. The recorder captures audio data in the specified format and passes packets for upstreaming to the React Native app.

  


  This is all working well and emitting a stream of audio data when I run my code on an iOS Simulator or real device.

  


  My problem is when I receive the audio stream in the backend, I find I'm unable to reliably decode the Opus stream using ffmpeg. (I wish to decode to PCM.)

  


  Whilst I could post up specific code to show what I'm doing in more detail, my question at this stage is more generic in nature:

  


  Is anyone familiar with the format of Opus audio stream that is generated by iOS AudioSession recorder under audio format kAudioFormatOpus ? Is anyone able to suggest proven conversion techniques? (e.g. some ffmpeg commands), or else hook me up with some links to format specs so I can figure out what is going on here ?

  


  The Apple Developer documentation contains zero useful information: https://developer.apple.com/documentation/coreaudiotypes/1572096-audio_data_format_identifiers/kaudioformatopus?changes=la__2&language=objc

  


  I have looked all over the internet, but I'm unable to find any useful spec info that corresponds to the stream that AVAudioSession recorder is outputting. I have seen a few posts which say Apple have not fully complied with the Opus spec, but I don't know enough about the proper structure of Opus to ascertain this for myself.

  


  Any help would be very much appreciated.

  


  Thanks all