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• avcodec/[e]ac3enc : Make encoders init-threadsafe, fix race

  3 décembre 2020, par Andreas Rheinhardt

  avcodec/[e]ac3enc : Make encoders init-threadsafe, fix race
  ff_eac3_exponent_init() set values twice when initializing a static
  
  table ; ergo the initialization code must not run concurrently with
  
  a running EAC-3 encoder. Yet this code is executed every time an EAC-3
  
  encoder is initialized. So use ff_thread_once() for this and also for a
  
  similar initialization performed for all AC-3 encoders to make them all
  
  init-threadsafe.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavcodec/ac3enc.c
  • [DH] libavcodec/ac3enc_fixed.c
  • [DH] libavcodec/ac3enc_float.c
  • [DH] libavcodec/eac3enc.c

• avcodec/pthread_slice : Don't use static variable, fix race

  28 novembre 2020, par Andreas Rheinhardt

  avcodec/pthread_slice : Don't use static variable, fix race
  ff_slice_thread_init() uses a static variable to hold a function
  
  pointer, although the value of said pointer needn't be saved between
  
  different runs of this function at all.
  The reason for this being so is probably that said pointer points to
  
  a static function (if used) ; but storage class specifiers like "static"
  
  are not part of the type of an object and so including it in the pointer
  
  declaration is wrong (anyway, "static" means different things in both
  
  contexts : for the function declaration it affects linkage, for the
  
  variable storage duration).
  Using a static variable here can lead to races, e.g. when initializing
  
  VP9 (for which said function pointer was added) and H.264 with slice
  
  threading. The latter has the FF_CODEC_CAP_INIT_THREADSAFE flag set and
  
  is therefore unaffected by the lock guarding initializations of
  
  decoders.
  Reviewed-by : Anton Khirnov <anton@khirnov.net>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavcodec/pthread_slice.c

• ffmpeg errors in the daemon

  3 octobre 2020, par smoto_shei

  I created a shell script to compress a video using ffmpeg(4.3.1).

  


  ffmpeg -y -i \
 '/var/www/System/Backend/Outputs/TempSaveMovie/200703_4_short_5fr_p2(100_20)_r(50_20).mp4' \
 -vcodec h264 -an \
 '/var/www/System/Backend/Outputs/MovieOutputs/200703_4_short_5fr_p2(100_20)_r(50_20).mp4'



  


  If you run this code from the console, it will run without problems.
In fact, we're using the python subscript.call() to execute it. It works fine too.

  


  cmd = 'sh /var/www/System/Backend/cv2toffmpeg.sh'
subprocess.call(cmd, shell=True)


  


  Secondly, if I run it from a daemonized python program, I'll get an error. I get the following error.
You'll get an error like this

  


  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from './Outputs/TempSaveMovie/200703_4_short_5fr_p2(100_20)_r(50_20).mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2mp41
    encoder         : Lavf58.35.100
  Duration: 00:00:06.15, start: 0.000000, bitrate: 10246 kb/s
    Stream #0:0(und): Video: mpeg4 (Simple Profile) (mp4v / 0x7634706D), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], 10244 kb/s, 13 fps, 13 tbr, 13312 tbn, 13 tbc (default)
    Metadata:
      handler_name    : VideoHandler
Stream mapping:
  Stream #0:0 -> #0:0 (mpeg4 (native) -> h264 (h264_nvenc))
Press [q] to stop, [?] for help
[mpeg4 @ 0x55cec17c5480] header damaged
[mpeg4 @ 0x55cec17c6840] header damaged
[mpeg4 @ 0x55cec1855f80] header damaged
[mpeg4 @ 0x55cec1866e00] header damaged
Output #0, mp4, to './Outputs/MovieOutputs/200703_4_short_5fr_p2(100_20)_r(50_20).mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2mp41
    encoder         : Lavf58.45.100
    Stream #0:0(und): Video: h264 (h264_nvenc) (Main) (avc1 / 0x31637661), yuv420p, 1280x720 [SAR 1:1 DAR 16:9], q=-1--1, 2000 kb/s, 13 fps, 13312 tbn, 13 tbc (default)
    Metadata:
      handler_name    : VideoHandler
      encoder         : Lavc58.91.100 h264_nvenc
    Side data:
      cpb: bitrate max/min/avg: 0/0/2000000 buffer size: 4000000 vbv_delay: N/A
Error while decoding stream #0:0: Invalid data found when processing input
[mpeg4 @ 0x55cec17c8780] header damaged
Error while decoding stream #0:0: Invalid data found when processing input
[mpeg4 @ 0x55cec17c5480] header damaged


  


  I think the problem is when you run it from a daemonized process. There seems to be a similar problem in the past.
Ffmpeg does not properly convert videos when run as daemon
I would like to ask for your help to solve this problem. Thank you for your help from Japan.