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• Generate individual HLS-compatible .ts segments on-demand by downloading as little bytes as possible from a remote input file

  27 janvier 2017, par Romain Cointepas

  I’m trying to generate individual HLS-compatible .ts segments on-demand by downloading/reading as little bytes as possible from a remote input file (hosted on a server supporting byte-ranges requests).

  One of the application for this would be to be able to transcode and play on Apple TV (via Airplay) a remote file that is not Airplay compatible, without having to download the entire file first.

  I am generating the playlist myself, and I have access to the ffprobe results for the remote file (that gives video duration, etc.).

  I have something working that plays via Airplay but with small video and audio glitches between each segments when I use the following command to generate each segment :

  ffmpeg -ss 60 -t 6 -i http://s3.amazonaws.com/misc-12345/avicii.vob -f mpegts -map 0:v:0 -map 0:a:0 -c:v libx264 -bsf:v h264_mp4toannexb -force_key_frames "expr:gte(t,n_forced*6)" -forced-idr 1 -pix_fmt yuv420p -colorspace bt709 -c:a aac -async 1 -preset ultrafast pipe:1

  Note : above command is for segment 11.ts, and in the m3u8 playlist I advertise each segment duration as 6 seconds.

  Here is a Youtube video showing the audio/video glitches between segments :
  https://www.youtube.com/watch?v=0vMwgbSfsu0

  The segment or hls modules of ffmpeg can’t be used because they both generate all the segments at once.

  I’ve been struggling on this for some days now and I would really appreciate some help !

• Piping FFmpeg output to Unity texture

  1er février 2021, par Sincress

  I'm working on a networking component where the server provides a Texture and sends it to FFmpeg to be encoded (h264_qsv), and sends it over the network. The client receives the stream (mp4 presumably), decodes it using FFmpeg again and displays it on a Texture.

  



  Currently this works very slowly since I am saving the texture to the disk before encoding it to a mp4 file (also saved to disk), and on the client side I am saving the .png texture to disk after decoding it so that I could use it in Unity.

  



  Server side FFmpeg process is started with process.StartInfo.Arguments = @" -y -i testimg.png -c:v h264_qsv -q 5 -look_ahead 0 -preset:v faster -crf 0 test.qsv.mp4"; currently and client side with process.StartInfo.Arguments = @" -y -i test.qsv.mp4 output.png";

  



  Since this needs to be very fast (30 fps at least) and real time, I need to pipe the Texture directly to the FFmpeg process. On the client side, I need to pipe the decoded data to the displayed Texture directly as well (opposed to saving it and then reading from disk).

  



  A few days of researching showed me that FFmpeg supports various pipelining options, including using data formats such as bmp_pipe (piped bmp sequence), bin(binary text), data (raw data) and image2pipe (piped image2 sequence) however documentation and examples on how to use these options are very scarce.

  



  Please help me : which format should I use (and how should it be used) ?

  


• Piping FFmpeg output to Unity texture

  13 décembre 2016, par Sincress

  I’m working on a networking component where the server provides a Texture and sends it to FFmpeg to be encoded (h264_qsv), and sends it over the network. The client receives the stream (mp4 presumably), decodes it using FFmpeg again and displays it on a Texture.

  Currently this works very slowly since I am saving the texture to the disk before encoding it to a mp4 file (also saved to disk), and on the client side I am saving the .png texture to disk after decoding it so that I could use it in Unity.

  Server side FFmpeg process is started with process.StartInfo.Arguments = @" -y -i testimg.png -c:v h264_qsv -q 5 -look_ahead 0 -preset:v faster -crf 0 test.qsv.mp4"; currently and client side with process.StartInfo.Arguments = @" -y -i test.qsv.mp4 output.png";

  Since this needs to be very fast (30 fps at least) and real time, I need to pipe the Texture directly to the FFmpeg process. On the client side, I need to pipe the decoded data to the displayed Texture directly as well (opposed to saving it and then reading from disk).

  A few days of researching showed me that FFmpeg supports various pipelining options, including using data formats such as bmp_pipe (piped bmp sequence), bin(binary text), data (raw data) and image2pipe (piped image2 sequence) however documentation and examples on how to use these options are very scarce.

  Please help me : which format should I use (and how should it be used) ?