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• Problem with understanding libvpx coder on ffmpeg - - Windows 10 [on hold]

  3 mars 2019, par Alex Deroza

  After reading some info I understood that vp9 not for single using, and it’s very slow in processing. it’s datacenter technologie. As for me I found best way to encode uhd content, hevc. for example, I trying to tell to you some kinds of this.. at first I encode my content by faster encoder which called as hevc, then upload to more powerfull hosting as Youtube, which reencoding my avc content in vpx, wich looks more economic when data transfer starting. that’s all. /SOLVED/

  P.S. I tried to recompile ffmpeg with vpx because thought that it faster encoder than hevc(265)

• libswresample/swresamplec : Err num(negative-size) was used as a function parameter

  8 décembre 2021, par Yu Yang

  libswresample/swresamplec : Err num(negative-size) was used as a function parameter
  If memory allocation fails, ERROR(ENOMEM) '-12' will be returned.
  
  When resample() is done first, the negative size param would cause buffer-overflow and SEGV in swri_rematrix().
  
  When swri_rematrix() is run first, resample() would not cause an error but Err num as a wrong parameter passing.
  
  Err num should be returned immediately. And remove an unneeded term from an assert.
  coredump info :
  
      #0 0x499517 in posix_memalign (/home/r1/ffmpeg/ffmpeg_4.4.1+0x499517)
  
      #1 0x6c1f0b4 in av_malloc /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavutil/mem.c:86:9
  
      #2 0x6c208fe in av_mallocz /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavutil/mem.c:239:17
  
      #3 0x6c207ad in av_mallocz_array /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavutil/mem.c:195:12
  
      #4 0x654b2e5 in swri_realloc_audio /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libswresample/swresample.c:418:14
  
      #5 0x654f9a1 in swr_convert_internal /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libswresample/swresample.c:601:17
  
      #6 0x654d2c0 in swr_convert /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libswresample/swresample.c:766:19
  
      #7 0x186cf56 in flush_frame /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/af_aresample.c:251:13
  
      #8 0x186a454 in request_frame /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/af_aresample.c:288:20
  
      #9 0x787d9c in ff_request_frame_to_filter /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/avfilter.c:459:15
  
      #10 0x7877f1 in forward_status_change /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/avfilter.c:1257:19
  
      #11 0x77ed7e in ff_filter_activate_default /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/avfilter.c:1288:20
  
      #12 0x77e4e1 in ff_filter_activate /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/avfilter.c:1441:11
  
      #13 0x793b3f in ff_filter_graph_run_once /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/avfiltergraph.c:1403:12
  
      #14 0x7a7bee in get_frame_internal /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/buffersink.c:131:19
  
      #15 0x7a7287 in av_buffersink_get_frame_flags /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/buffersink.c:142:12
  
      #16 0x792888 in avfilter_graph_request_oldest /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/libavfilter/avfiltergraph.c:1356:17
  
      #17 0x5d07df in transcode_from_filter /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/fftools/ffmpeg.c:4639:11
  
      #18 0x59e557 in transcode_step /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/fftools/ffmpeg.c:4729:20
  
      #19 0x593970 in transcode /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/fftools/ffmpeg.c:4805:15
  
      #20 0x58f7a4 in main /home/r1/ffmpeg/ffmpeg-4.4.1/build/src/fftools/ffmpeg.c:5010:9
  
      #21 0x7f6fd2dee0b2 in __libc_start_main /build/glibc-eX1tMB/glibc-2.31/csu/../csu/libc-start.c:308:16
  SUMMARY : AddressSanitizer : negative-size-param (/home/r1/ffmpeg/ffmpeg_4.4.1+0x497e67) in __asan_memcpy
  Reported-by : TOTE Robot <oslab@tsinghua.edu.cn>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libswresample/swresample.c

• how to combine multiple ffmpeg commands into one command ?

  22 juin 2023, par sonam

  Right now, I am running separate commands to reduce volume, add fade in at start and fade out audio at end, add silence to start and end of audio. How do I combine all these single command into one ?

  


  ffmpeg -y -i /home/music/memories.mp3 -filter:a "volume=0.5" -write_xing 0 /home/music/memories-volume.mp3
ffmpeg -y -i /home/music/memories-volume.mp3 -af "afade=in:st=0:d=5,afade=t=out:st=5:d=5" -write_xing 0 /home/music/memories-fade.mp3
ffmpeg -y -i /home/music/memories-fade.mp3 -af areverse,apad=pad_dur=5s,areverse -write_xing 0 /home/music/memories-silence-front.mp3
ffmpeg -y -i /home/music/memories-silence-front.mp3  -af apad=pad_dur=5s -write_xing 0 /home/music/memories-silence-end.mp3