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• skip buffered packets while decoding

  19 février 2023, par nulladdr

  I've got a Server that encodes live data and sends it as AVPackets, a Client decodes (H.264) and previews the data.
  
Sometimes because of connectivity issues the packets don't arrive at all, get buffered and the Client gets multiple at the same time.


  


  Now if the Client decodes all the buffered packets and such gaps repeat multiple times,
  
the lag keeps growing and the stream is no longer live.

  


  The priority is to keep the stream live over quality and discontinuities.

  


  

  • is it allowed to manually skip an AVPacket while decoding ?

  


  • is there an option to tell the Decoder to discard packets that are old (maybe old timestamp) ?

  


  • any other options ?

  


  


• configure : rework parsing —cpu arguments to support all features unless blacklisted

  17 septembre 2023, par James Almer

  configure : rework parsing —cpu arguments to support all features unless blacklisted
  Keeping an ever growing list of CPUs just to pass -march to the compiler and
  
  enable fast_cmov is a waste of time. Every CPU we know has limitations is
  
  already handled here, so just fallback to enabling everything when a passed in
  
  argument is not one of those.
  This will enable optimizations for CPU architectures released in the past 7 or
  
  so years with supported GCC and clang compilers when used as argument in
  
  configure, instead of silently ignoring them.
  Signed-off-by : James Almer <jamrial@gmail.com>
  

  • [DH] configure

• Getting realtime output of ffmpeg with pexpect

  27 février 2014, par Shuman

  hi i'm trying to get the progress info when calling ffmpeg command line tool, with pexpect, i can get the progress with regex, but the problem is after a few seconds, maybe 20 or 10sec, pexpect stops getting new print outs from ffmpeg, it's still running, i saw the output file size growing. am i doing something wrong ?

  cmd = 'ffmpeg -i rtmp://xxxx -c copy -absf aac_adtstoasc /usr/tmp/tmp/out.mp4'
  
  
  
  import os
  
  import re
  
  import time
  
  import subprocess 
  
  
  
  
  
  import pexpect
  
  
  
  thread = pexpect.spawn(cmd)
  
  
  
  print 'started'
  
  
  
  reo = re.compile("""\S+\s+(?P\d+)  # frame
  
                       \s\S+\s+(?P<fps>\d+)           # fps
  
                       \sq=(?P<q>\S+)                    # q
  
                       \s\S+\s+(?P<size>\S+)          # size
  
                       \stime=(?P<time>\S+)           # time
  
                       \sbitrate=(?P<bitrate>[\d\.]+) # bitrate
  
                       """, re.X)
  
  
  
  durationReo = (&#39;(?&lt;=Duration:\s)\S+(?=,)&#39;)
  
  
  
  cpl = thread.compile_pattern_list([
  
      pexpect.EOF,
  
      reo,
  
      durationReo
  
  ])
  
  
  
  
  
  while True:
  
      i = thread.expect_list(cpl, timeout=None)
  
      if i == 0: # EOF
  
          print "the sub process exited"
  
          break
  
      elif i == 1:
  
          frame_number = thread.match.group(0)
  
          print frame_number
  
      elif i == 2:
  
          durationLine = thread.match.group(0).strip()
  
          print &#39;Duration:&#39;, durationLine
  
  </bitrate></time></size></q></fps>

  the output is

  started                                                                                   
  
  Duration: 03:55:42.00                                                                     
  
  frame=   74 fps= 55 q=-1.0 size=     984kB time=00:00:06.17 bitrate=1304.5                
  
  frame=   89 fps= 43 q=-1.0 size=    1197kB time=00:00:07.43 bitrate=1319.8                
  
  frame=  113 fps= 41 q=-1.0 size=    1407kB time=00:00:09.33 bitrate=1234.8
  
  frame=  125 fps= 32 q=-1.0 size=    1613kB time=00:00:10.35 bitrate=1275.6
  
  frame=  132 fps= 29 q=-1.0 size=    1705kB time=00:00:10.95 bitrate=1274.7
  
  frame=  135 fps= 26 q=-1.0 size=    1825kB time=00:00:11.23 bitrate=1330.6
  
  frame=  140 fps= 24 q=-1.0 size=    2022kB time=00:00:11.60 bitrate=1426.5
  
  frame=  140 fps= 21 q=-1.0 size=    2097kB time=00:00:11.70 bitrate=1467.7
  
  frame=  142 fps= 19 q=-1.0 size=    2224kB time=00:00:11.79 bitrate=1544.4
  
  frame=  143 fps= 17 q=-1.0 size=    2447kB time=00:00:11.98 bitrate=1672.8
  
  frame=  145 fps= 16 q=-1.0 size=    2687kB time=00:00:12.07 bitrate=1822.8
  
  frame=  155 fps= 15 q=-1.0 size=    2780kB time=00:00:12.95 bitrate=1757.6
  
  frame=  163 fps= 15 q=-1.0 size=    2940kB time=00:00:13.65 bitrate=1764.2
  
  frame=  167 fps= 14 q=-1.0 size=    3062kB time=00:00:13.83 bitrate=1812.3
  
  frame=  168 fps= 13 q=-1.0 size=    3149kB time=00:00:14.02 bitrate=1839.4
  
  frame=  190 fps= 14 q=-1.0 size=    3322kB time=00:00:15.78 bitrate=1723.6
  
  frame=  213 fps= 15 q=-1.0 size=    3481kB time=00:00:17.78 bitrate=1603.4
  
  frame=  235 fps= 16 q=-1.0 size=    3671kB time=00:00:19.59 bitrate=1534.3
  
  frame=  244 fps= 16 q=-1.0 size=    3790kB time=00:00:20.29 bitrate=1530.0
  
  frame=  256 fps= 16 q=-1.0 size=    3909kB time=00:00:21.31 bitrate=1502.1
  
  frame=  276 fps= 16 q=-1.0 size=    4029kB time=00:00:22.94 bitrate=1438.8
  
  frame=  299 fps= 17 q=-1.0 size=    4177kB time=00:00:24.93 bitrate=1372.1
  
  frame=  339 fps= 19 q=-1.0 size=    4388kB time=00:00:28.28 bitrate=1270.9
  
  frame=  363 fps= 19 q=-1.0 size=    4557kB time=00:00:30.18 bitrate=1236.8
  
  frame=  405 fps= 20 q=-1.0 size=    4587kB time=00:00:33.76 bitrate=1113.1
  
  frame=  421 fps= 20 q=-1.0 size=    4598kB time=00:00:35.15 bitrate=1071.4

  it stops here but the code is still running. the file size is still growing and the code didn't exit, so it's not because of the timeout bug in pexpect.

  and also , if user press ctrl+c to terminate the main program, ffmpeg still runs in the bg, how do i also tell it to exit ?

  edit : i found that the culprit might be ffmpeg is not printing out all the info after 10 lines or so. it only update the display where it needs to be changed.so the regex is not matching, so what to do now , make 6 seperate regex ?

  edit2 : it seems if i use this regex, it works...

  reo = re.compile("""frame=\s*(?P\d+)  # frame
  
                       \sfps=\s*(?P<fps>\d+)           # fps
  
                       \sq=\s*(?P<q>\S+)                    # q
  
                       \ssize=\s*(?P<size>\S+)          # size
  
                       \stime=\s*(?P<time>\S+)           # time
  
                       \sbitrate=\s*(?P<bitrate>[\d\.]+) # bitrate
  
                       """, re.X)
  
  </bitrate></time></size></q></fps>

  it's saying only match when frame number is updated, ( maybe this implies all the other text are also updated ? )