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• How do I get ffmpeg to concat 1 second from a list of files ?

  13 juin 2023, par Stephen Fluin

  I have about a thousand video clips and I've got ffmpeg and an ffmpeg file list setup like this :

  



  file /path/to/1.mp4
file /path/to/2.mp4
...
file /path/to/1000.mp4


  



  I want to concatenate the first second of each clip into an output clip. I've experimented with duration and outpoints specified in the file list, but neither seems to do what I want.

  



  Here's the documentation I've read which I found unclear and lacking an example using the full API : https://ffmpeg.org/ffmpeg-formats.html#concat

  



  Here's the closest I've come (concat the entirety of all files at 100x speed) :

  



  ffmpeg -f concat -safe 0 -i ~/glass-videos.ffmpeg.txt -filter:v "setpts=PTS/100" -an output.mp4

  


• FFmpeg Video is not shown, after encoding audio and video

  19 mars 2019, par Ashutosh Singla

  I’m using FFMPEG to encode my video which also has audio in it

  ffmpeg -i .\A0002780.kava23_Fin.avi -c:v libx265 -preset ultrafast -crf 20 -c:a aac output.mp4

  This command is working OK with no errors. But when I play the video, I can hear only audio and can’t see the video.

  Here are the logs of the command :

  ffmpeg version N-83280-gcba4f0e Copyright (c) 2000-2017 the FFmpeg developers
  
  built with gcc 5.4.0 (GCC)
  
  configuration: --enable-gpl --enable-version3 --enable-cuda --enable-cuvid 
  
  --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-nvenc --enable-     avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls 
  
  --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b -- 
  
  enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm -- 
  
  enable-libilbc --enable-libmodplug --enable-libmp3lame --enable- 
  
  libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264 -- 
  
  enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libsnappy -- 
  
  enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame -- 
  
  enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable- 
  
  libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable- 
  
  libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma - 
  
  -enable-decklink --enable-zlib
  
  
  
  
  
  libavutil      55. 45.100 / 55. 45.100
  
    libavcodec     57. 75.100 / 57. 75.100
  
    libavformat    57. 65.100 / 57. 65.100
  
    libavdevice    57.  2.100 / 57.  2.100
  
    libavfilter     6. 71.100 /  6. 71.100
  
    libswscale      4.  3.101 /  4.  3.101
  
    libswresample   2.  4.100 /  2.  4.100
  
    libpostproc    54.  2.100 / 54.  2.100
  
  [avi @ 0000000000f973a0] Stream #0: not enough frames to estimate rate; consider increasing probesize
  
  Guessed Channel Layout for Input Stream #0.1 : stereo
  
  Input #0, avi, from '.\A0002780.kava23_Fin.avi':
  
    Duration: 00:00:30.00, start: 0.000000, bitrate: 17697237 kb/s
  
      Stream #0:0: Video: rawvideo, bgr24, 7680x3840, 25 fps, 25 tbr, 25 tbn, 25 tbc
  
      Stream #0:1: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, stereo, s16, 1411 kb/s
  
  x265 [info]: HEVC encoder version 2.2
  
  x265 [info]: build info [Windows][GCC 5.4.0][64 bit] 8bit
  
  x265 [info]: using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX AVX2 FMA3 LZCNT BMI2
  
  x265 [info]: Main profile, Level-6 (Main tier)
  
  x265 [info]: Thread pool created using 8 threads
  
  x265 [info]: Slices                              : 1
  
  x265 [info]: frame threads / pool features       : 3 / wpp(120 rows)
  
  x265 [info]: Coding QT: max CU size, min CU size : 32 / 16
  
  x265 [info]: Residual QT: max TU size, max depth : 32 / 1 inter / 1 intra
  
  x265 [info]: ME / range / subpel / merge         : dia / 57 / 0 / 2
  
  x265 [info]: Keyframe min / max / scenecut / bias: 25 / 250 / 0 / 5.00
  
  x265 [info]: Lookahead / bframes / badapt        : 5 / 3 / 0
  
  x265 [info]: b-pyramid / weightp / weightb       : 1 / 0 / 0
  
  x265 [info]: References / ref-limit  cu / depth  : 1 / off / off
  
  x265 [info]: AQ: mode / str / qg-size / cu-tree  : 1 / 0.0 / 32 / 1
  
  x265 [info]: Rate Control / qCompress            : CRF-20.0 / 0.60
  
  x265 [info]: tools: rd=2 psy-rd=2.00 early-skip rskip tmvp fast-intra
  
  x265 [info]: tools: strong-intra-smoothing lslices=8 deblock
  
  Output #0, mp4, to 'output.mp4':
  
    Metadata:
  
      encoder         : Lavf57.65.100
  
      Stream #0:0: Video: hevc (libx265) ([35][0][0][0] / 0x0023), yuv420p, 7680x3840, q=2-31, 25 fps, 12800 tbn, 25 tbc
  
      Metadata:
  
        encoder         : Lavc57.75.100 libx265
  
      Stream #0:1: Audio: aac (LC) ([64][0][0][0] / 0x0040), 44100 Hz, stereo, fltp, 128 kb/s
  
      Metadata:
  
        encoder         : Lavc57.75.100 aac
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (rawvideo (native) -> hevc (libx265))
  
    Stream #0:1 -> #0:1 (pcm_s16le (native) -> aac (native))
  
  Press [q] to stop, [?] for help
  
  frame=  750 fps=0.7 q=-0.0 Lsize=   17320kB time=00:00:30.04 bitrate=4722.1kbits/s speed=0.0269x
  
  video:16823kB audio:469kB subtitle:0kB other streams:0kB global headers:2kB muxing overhead: 0.159117%
  
  x265 [info]: frame I:      3, Avg QP:22.35  kb/s: 250515.20
  
  x265 [info]: frame P:    187, Avg QP:24.28  kb/s: 10607.54
  
  x265 [info]: frame B:    560, Avg QP:27.67  kb/s: 1267.19
  
  x265 [info]: consecutive B-frames: 1.1% 1.1% 0.0% 97.9%
  
  
  
  encoded 750 frames in 1117.63s (0.67 fps), 4593.04 kb/s, Avg QP:26.80
  
  [aac @ 00000000027c91e0] Qavg: 456.871 

  It seems that there is no error and I can see that video and audio are encoded properly.

  Any idea ?

• How can I broadcast a Twilio (group room) video conference ?

  2 novembre 2022, par Danish

  I have been trying different solutions/approaches for last few days and posting here to get some more options.

  



  I am planning to use Twilio's Programmable Video solution with Group room (upto 50 participants) to allow hosts/presenters to join video conference meeting. Right now I am able to setup and get started with quickstart example here

  



  Also, in parallel, I need to be able to broadcast that live meeting room through RTMP/HLS (audio+video) streaming that can be viewed (through another portal) by large user set (ideally around 10k+)

  



  Twilio support team suggested - integrating Twilio Video with Wowza using screenscrapping and ffmpeg (i.e. render the video into a (maybe virtual) screen, capture it and send to Wowza using ffmpeg.)

  



  I am new to both ffmpeg and wowza. However, I am looking to see high level solution which can be used to achieve this (with minimum hanging parts).

  



  Ideal flow i can think of is

  



  

  • Start a Twilio video conference room with actual presenters

  


  • all participants share there video and audio tracks with each other in the room - standard behavior

  


  • a new ghost-participant joins-in from stand-alone server (from wowza or SIP) and subscribes to audio-video tracks in conference.

  


  • arrange & combine those tracks into one channel and stream it as HLS

  


  • this ghost-participant will also be able to identify dominant speaker and re-arrange video tracks to show current speaker occupying bigger space (just like zoom)

  


  • and of course, this streamed video (with audio) will be one-way and viewers cannot interact. Just see be able to see the room broadcasting.

  


  



  Also/FYI
I have tried exploring few more options below (with no success)

  



  


  1. a blog here explain how can we broadcast a twilio audio
conference. At the bottom it also mention about video streaming. but, I am not getting how can we use SIP to get video stream that can be broadcasted. Also, how can I manipulate video tracks to show dominant speakers in full screen view Vs other participant in thumbnail view i.e. custom layouts.

  


  2. I also explored option of Wowza WebRTC streaming to achieve this, but it has got other technical challenges with setting up video room with multiple participants. I am going to reach out to them to see if this use-case is possible with their offering.

  


  3. I am looking for something as simple as here - dial as guest participant into video room from standalone streaming server/wowza server. And get output as single stream to broadcast.

  


  



  Any other pointers or links to solutions would be helpful.