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• Non-monotonous DTS after 26:30:02.81 recording time

  24 mars, par micha

  I record an hls stream and after 26:30:02.81 there come the message :

  



  [http @ 0x558330f5ba80] Opening 'http://de-origin-live-be-01.3qsdn.com:8081/3279/996191_PwxkbnqRThCDGXVr/l_94_95438333_16449.ts?nimblesessionid=2106' for reading
frame=2289669 fps= 24 q=-1.0 size=25056768kB time=26:30:02.81 bitrate=2151.6kbits/s speed=   1x    
[mpegts @ 0x558330f07280] Invalid timestamps stream=0, pts=10378, dts=8589926250, size=11200
[mpegts @ 0x558330f07280] Invalid timestamps stream=0, pts=2908, dts=8589929940, size=3407
[mp4 @ 0x558330f20bc0] Non-monotonous DTS in output stream 0:0; previous: 8586744840, current: -3185972; changing to 8586744841. This may result in incorrect timestamps in the output file.
[mp4 @ 0x558330f20bc0] Non-monotonous DTS in output stream 0:1; previous: 4579598864, current: -1698561; changing to 4579598865. This may result in incorrect timestamps in the output file.
[mp4 @ 0x558330f20bc0] Non-monotonous DTS in output stream 0:1; previous: 4579598865, current: -1697537; changing to 4579598866. This may result in incorrect timestamps in the output file.
[mp4 @ 0x558330f20bc0] Non-monotonous DTS in output stream 0:1; previous: 4579598866, current: -1696513; changing to 4579598867. This may result in incorrect timestamps in the output file.
[mp4 @ 0x558330f20bc0] Non-monotonous DTS in output stream 0:0; previous: 8586744841, current: -3182282; changing to 8586744842. This may result in incorrect timestamps in the output file.
[mp4 @ 0x558330f20bc0] Non-monotonous DTS in output stream 0:1; previous: 4579598867, current: -1695489; changing to 4579598868. This may result in incorrect timestamps in the output file.
[mp4 @ 0x558330f20bc0] Non-monotonous DTS in output stream 0:1; previous: 4579598868, current: -1694465; changing to 4579598869. This may result in incorrect timestamps in the output file.
[mp4 @ 0x558330f20bc0] Non-monotonous DTS in output stream 0:1; previous: 4579598869, current: -1693441; changing to 4579598870. This may result in incorrect timestamps in the output file.
[mp4 @ 0x558330f20bc0] Non-monotonous DTS in output stream 0:0; previous: 8586744842, current: -3178502; changing to 8586744843. This may result in incorrect timestamps in the output file.
[mp4 @ 0x558330f20bc0] Non-monotonous DTS in output stream 0:0; previous: 8586744843, current: -3174722; changing to 8586744844. This may result in incorrect timestamps in the output file.


  



  There is no more video written to the file at this time but ffmpeg is not stopping. If i stop it manual after 30 hours the file is only 26 hours 30 minutes long.

  



  How to reproduce :

  



  ffmpeg -progress recorder.progress -reconnect 1 -user_agent 'sdn/1.0' -i http://source/playlist.m3u8 -codec copy -bsf:a aac_adtstoasc record.mp4

ffmpeg version 4.2.2 Copyright (c) 2000-2019 the FFmpeg developers
  built with gcc 7 (Ubuntu 7.4.0-1ubuntu1~18.04.1)
  configuration: --disable-debug --disable-doc --disable-ffplay --enable-shared --enable-avresample --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-gpl --enable-libass --enable-libfreetype --enable-libvidstab --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libxcb --enable-libx265 --enable-libxvid --enable-libx264 --enable-nonfree --enable-openssl --enable-libfdk_aac --enable-libkvazaar --enable-libaom --extra-libs=-lpthread --enable-postproc --enable-small --enable-version3 --enable-libbluray --enable-demuxer=dash --enable-decoder=hevc --enable-libxml2 --extra-cflags=-I/opt/ffmpeg/include --extra-ldflags=-L/opt/ffmpeg/lib --extra-libs=-ldl --prefix=/opt/ffmpeg
  libavutil      56. 31.100 / 56. 31.100
  libavcodec     58. 54.100 / 58. 54.100
  libavformat    58. 29.100 / 58. 29.100
  libavdevice    58.  8.100 / 58.  8.100
  libavfilter     7. 57.100 /  7. 57.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  5.100 /  5.  5.100
  libswresample   3.  5.100 /  3.  5.100
  libpostproc    55.  5.100 / 55.  5.100


  


• How To Play Hardware Accelerated Video on A Mac

  28 mai 2013, par Multimedia Mike — General

  I have a friend who was considering purchasing a Mac Mini recently. At the time of this writing, there are 3 desktop models (and 2 more “server” models).

  
  
  

  The cheapest one is a Core i5 2.5 GHz. Then there are 2 Core i7 models : 2.3 GHz and 2.6 GHz. The difference between the latter 2 is US$100. The only appreciable technical difference is the extra 0.3 GHz and the choice came down to those 2.

  He asked me which one would be able to play HD video at full frame rate. I found this query puzzling. But then, I have been “in the biz” for a bit too long. Whether or not a computer or device can play a video well depends on a lot of factors.

  Hardware Support
  First of all, looking at the raw speed of the general-purpose CPU inside of a computer as a gauge of video playback performance is generally misguided in this day and age. In general, we have a video standard (H.264, which I’ll focus on for this post) and many bits of hardware are able to accelerate decoding. So, the question is not whether the CPU can decode the data in real time, but can any other hardware in the device (likely the graphics hardware) handle it ? These machines have Intel HD 4000 graphics and, per my reading of the literature, they are capable of accelerating H.264 video decoding.

  Great, so the hardware supports accelerated decoding. So it’s a done deal, right ? Not quite…

  Operating System Support
  An application can’t do anything pertaining to hardware without permission from the operating system. So the next question is : Does Mac OS X allow an application to access accelerated video decoding hardware if it’s available ? This used to be a contentious matter (notably, Adobe Flash Player was unable to accelerate H.264 playback on Mac in the absence of such an API) but then Apple released an official API detailed in Technical Note TN2267.

  So, does this mean that video is magically accelerated ? Nope, we’re still not there yet…

  Application Support
  It’s great that all of these underlying pieces are in place, but if an individual application chooses to decode the video directly on the CPU, it’s all for naught. An application needs to query the facilities and direct data through the API if it wants to leverage the acceleration. Obviously, at this point it becomes a matter of “which application ?”

  My friend eventually opted to get the pricier of the desktop Mac Mini models and we ran some ad-hoc tests since I was curious how widespread the acceleration support is among Mac multimedia players. Here are some programs I wanted to test, playing 1080p H.264 :

  • Apple QuickTime Player
  • VLC
  • YouTube with Flash Player (any browser)
  • YouTube with Safari/HTML5
  • YouTube with Chrome/HTML5
  • YouTube with Firefox/HTML5
  • Netflix

  I didn’t take exhaustive notes but my impromptu tests revealed QuickTime Player was, far and away, the most performant player, occupying only around 5% of the CPU according to the Mac OS X System Profiler graph (which is likely largely spent on audio decoding).

  VLC consistently required 20-30% CPU, so it’s probably leveraging some acceleration facilities. I think that Flash Player and the various HTML5 elements performed similarly (their multi-process architectures can make such a trivial profiling test difficult).

  The outlier was Netflix running in Firefox via Microsoft’s Silverlight plugin. Of course, the inner workings of Netflix’s technology are opaque to outsiders and we don’t even know if it uses H.264. It may very well use Microsoft’s VC-1 which is not a capability provided by the Mac OS X acceleration API (it doesn’t look like the Intel HD 4000 chip can handle it either). I have never seen any data one way or another about how Netflix encodes video. However, I was able to see that Netflix required an enormous amount of CPU muscle on the Mac platform.

  Conclusion
  The foregoing is a slight simplification of the video playback pipeline. There are some other considerations, most notably how the video is displayed afterwards. To circle back around to the original question : Can the Mac Mini handle full HD video playback ? As my friend found, the meager Mac Mini can do an admirable job at playing full HD video without loading down the CPU.

• Can ffmpeg extract multiple parts of a video file in a single command ?

  18 décembre 2020, par rcliao

  I have some huge MPEG files that is 24 hours long, and I need to extract a few parts (about 30 minutes each) of it into frame sequences (still images). I tried using commands like following :

  


  ffmpeg -i input.mpeg -ss 4:00:00 -to 4:30:00 outpath1\%05d.png
ffmpeg -i input.mpeg -ss 6:00:00 -to 6:30:00 outpath2\%05d.png
...


  


  But it seems that each time it is executed, ffmpeg scans the file from the beginning, causing the process to be very slow.

  


  For example, when I execute the above commands to extract the part of 4:00:00-4:30:00, ffmpeg will scan from 0:00:00 to 4:00:00, start extracting the image sequence, and stop at 4:30:00 ; and then I execute another command to extract the part of 6:00:00-6:30:00, and ffmpeg scans from 0:00:00 again to 6:00:00, and then start extracting.

  


  So I wanted to simplify this process to save time. Is there a way to extract multiple parts in a single command ? Like scans from 0:00:00 to 4:00:00, start extracting to 4:30:00, stop extracting and continue scanning to 6:00:00, and start extracting again...until the last part. Can ffmpeg do this ?