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• Streaming vulkan framebuffer over HLS

  19 novembre 2022, par SOSparachuter1

  I need to stream frames from a native android Vulkan application of mine, I'm successfully copying data off my framebuffer and the raw frame data is ready for encoding. However I'm torn on what the best next steps would be.

  


  The raw image needs to be encoded to JPEG, then transported via HLS which will end up at some HTTP server which will host the playlist externally.

  


  The main point of contention is how I can encode the raw frame and then serve it to the HTTP server.

  


  I assume I'll need to start a tcp server to send raw frames to ffmpeg/gstreamer pipeline for encoding, but I'm not sure what that command would look like. Or whether there is a better way to do this.

  


• ffmpeg : Merge multiple mpeg videos while switching audio tracks

  12 octobre 2015, par Mark Schneider

  I have 7 mpeg files that were converted from images and videos as follows :

  001.mpeg - created from a still image
  002.mpeg - created from a still image
  003.mpeg - video with an audio track
  004.mpeg - created from a still image
  005.mpeg - video with an audio track
  006.mpeg - created from a still image

  I need to concatenate them together along with an audio soundtrack into a single mp4 file. While the mpeg files created from images are being displayed, I’d like to hear the audio soundtrack, however, while the videos (003.mpeg and 005.mpeg) are being displayed, I’d like to hear their respective audio tracks instead of the soundtrack.

  I’m able to stitch together the files with the audio soundtrack playing throughout using these commands :

  ffmpeg -i concat:"001.mpeg|002.mpeg|003.mpeg|004.mpeg|005.mpeg|007.mpeg" -c copy video_before_adding_audio.mp4

  ffmpeg i video_before_adding_audio.mp4 -i soundtrack.mp3 -map 0:0 -map 1 -vcodec copy -acodec aac -strict experimental -shortest vue.mp4

  Is there a way to get ffmpeg to “duck” the audio soundtrack down to 10% volume while the videos are being shown ? If not, is there a way to duck the audio entirely while those files are being shown ?

  As a secondary question, so as to not have abrupt changes in the sound when switching between the soundtrack and the video’s audio tracks, is there a way to instruct ffmpeg fade the soundtrack out just as 003.mpeg is being reached (maybe over 1/4 second) and to fade it back in when 004.mpeg starts (and to the same for 005.mpeg and 006.mpeg) ?

  Here is the ffprobe output for the 003.mpeg and 005.mpeg files :

  ffprobe version 2.5 Copyright (c) 2007-2014 the FFmpeg developers
  
    built on Dec 10 2014 19:03:38 with Apple LLVM version 6.0 (clang-600.0.56) (based on LLVM 3.5svn)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/2.5 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-libx264 --enable-libmp3lame --enable-libxvid --enable-libvo-aacenc --enable-vda
  
    libavutil      54. 15.100 / 54. 15.100
  
    libavcodec     56. 13.100 / 56. 13.100
  
    libavformat    56. 15.102 / 56. 15.102
  
    libavdevice    56.  3.100 / 56.  3.100
  
    libavfilter     5.  2.103 /  5.  2.103
  
    libavresample   2.  1.  0 /  2.  1.  0
  
    libswscale      3.  1.101 /  3.  1.101
  
    libswresample   1.  1.100 /  1.  1.100
  
    libpostproc    53.  3.100 / 53.  3.100
  
  Input #0, mpegts, from '006.vuepart.mpeg':
  
    Duration: 00:00:07.59, start: 1.555756, bitrate: 2356 kb/s
  
    Program 1
  
      Metadata:
  
        service_name    : Service01
  
        service_provider: FFmpeg
  
      Stream #0:0[0x100]: Video: h264 (Main) ([27][0][0][0] / 0x001B), yuv420p, 800x600, 12 fps, 12 tbr, 90k tbn, 24 tbc
  
      Stream #0:1[0x101](und): Audio: mp2 ([3][0][0][0] / 0x0003), 44100 Hz, mono, s16p, 384 kb/s

  Here is the ffprobe output for the mpeg file created from still images :

  ffprobe version 2.5 Copyright (c) 2007-2014 the FFmpeg developers
  
    built on Dec 10 2014 19:03:38 with Apple LLVM version 6.0 (clang-600.0.56) (based on LLVM 3.5svn)
  
    configuration: --prefix=/usr/local/Cellar/ffmpeg/2.5 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-libx264 --enable-libmp3lame --enable-libxvid --enable-libvo-aacenc --enable-vda
  
    libavutil      54. 15.100 / 54. 15.100
  
    libavcodec     56. 13.100 / 56. 13.100
  
    libavformat    56. 15.102 / 56. 15.102
  
    libavdevice    56.  3.100 / 56.  3.100
  
    libavfilter     5.  2.103 /  5.  2.103
  
    libavresample   2.  1.  0 /  2.  1.  0
  
    libswscale      3.  1.101 /  3.  1.101
  
    libswresample   1.  1.100 /  1.  1.100
  
    libpostproc    53.  3.100 / 53.  3.100
  
  Input #0, mpegts, from '001.vuepart.mpeg':
  
    Duration: 00:00:02.54, start: 1.522422, bitrate: 609 kb/s
  
    Program 1
  
      Metadata:
  
        service_name    : Service01
  
        service_provider: FFmpeg
  
      Stream #0:0[0x100]: Video: h264 (High) ([27][0][0][0] / 0x001B), yuvj420p(pc), 800x600 [SAR 1:1 DAR 4:3], 15 fps, 15 tbr, 90k tbn, 30 tbc
  
      Stream #0:1[0x101]: Audio: mp2 ([3][0][0][0] / 0x0003), 44100 Hz, mono, s16p, 384 kb/s

  Note : I’ve added a silent audio track to the still images.

• Low Latency Desktopstreaming with ffmpeg (p2p)

  8 avril 2016, par Gring

  I’m trying to stream my Desktop from one Pc to another with udp. Unfortunately the Latency is pretty high (I already could reduce it from about 15 Seconds to 2 Seconds, in tests where I run client and host on the same PC.
  My Hostcommand looks like this :

  ffmpeg -f dshow  -framerate 24 -i video=screen-capture-recorder -vf scale=1280:720 -vcodec libx264 -force_key_frames "expr:gte(t,n_forced*2)" -pix_fmt yuv420p -tune zerolatency -preset ultrafast -f mpegts udp://239.255.1.2:1234

  My Clientcommand looks like this :

  ffplay -fflags nobuffer -infbuf -fast -framedrop -vf "setpts=(PTS*0.95)" udp://239.255.1.2:1234

  Any Ideas, how to get this even faster ?