Recherche avancée

Sur d’autres sites (7540)

• avcodec/vbn(dec|enc) : Remove empty close function

  12 avril 2022, par Andreas Rheinhardt

  avcodec/vbn(dec|enc) : Remove empty close function
  Reviewed-by : Marton Balint <cus@passwd.hu>
  
  Reviewed-by : Paul B Mahol <onemda@gmail.com>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavcodec/vbndec.c
  • [DH] libavcodec/vbnenc.c

• Write empty packets into avi file ffmpeg

  26 avril 2022, par hagor

  A task :
I have a trusted video event detector. I trust to my event detector for 100% and I want to write an uncompressed frame to my avi containter only if my event detector produces "true" result.
For frames, when my event detector is producing "false" I would like to write an empty packet because I want to know that there was a frame without event happening.
Is it possible to keep AVI file alive ? Or do I need to write my own player in this case ?

  


  Another option is to calculate timestamps manually and set dts/pts to that calculated time.
Drawback : I will need to recalculate timestamps to understand how many frames were between events.

  


  I am using :

  


  


  av_write_frame(AVFormatContext, AVPacket) ;

  


  


  and

  


  


  av_interleaved_write_frame(AVFormatContext, AVPacket) ;

  


  


  What is your suggestion/idea ?
Thank you in advance.

  


• swresample/resample : Properly empty MMX state

  11 juin 2022, par Andreas Rheinhardt

  swresample/resample : Properly empty MMX state
  There is a x86-32 MMXEXT implementation for resampling
  
  planar 16bit data. multiple_resample() therefore calls
  
  emms_c() if it thinks that this needed. And this is bad :
  1. It is a maintenance nightmare because changes to the
  
  x86 resample DSP code would necessitate changes to the check
  
  whether to call emms_c().
  
  2. The return value of av_get_cpu_flags() does not tell
  
  whether the MMX DSP functions are in use, as they could
  
  have been overridden by av_force_cpu_flags().
  
  3. The MMX DSP functions will never be overridden in case of
  
  an x86-32 build with —disable-sse2. In this scenario lots of
  
  resampling tests (like swr-resample_exact_lin_async-s16p-8000-48000)
  
  fail because the cpuflags indicate that SSE2 is available
  
  (presuming that the test is run on a CPU with SSE2).
  
  4. The check includes a call to av_get_cpu_flags(). This is not
  
  optimized away for arches other than x86-32.
  
  5. The check takes about as much time as emms_c() itself,
  
  making it pointless.
  This commit therefore removes the check and calls emms_c()
  
  unconditionally (it is a no-op for non-x86).
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libswresample/resample.c