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• HLS implementation with FFmpeg

  6 juin 2017, par Joseph K

  I am trying to implement HLS using FFmpeg for transcoding + segmenting but have been facing a couple of issues that have been bugging me for the past week.

  Issue

  Webserver currently receives live MP4 fragments being recorded on-the-go and needs to take care of transcoding and segmentation.

  As mp4 fragments are being received, they need to be encoded. Then segmented. If i run a segmenter (be it ffmpeg or apple mediastreamsegmenter), every mp4 fragment is being treated as a VOD by itself and I’m not being able to integrate them as part of a larger live event implementation.

  I thought of a solution where every time I receive an mp4 fragment, I first use fmpeg to concatenate it with previous ones to form the larger mp4 that I then pass to be segmented for HLS. That did not work either because the entire stream has to be re-segmented each and every time and existing TS fragments replaced by new ones that are similar yet shifted in time.

  Implementation 1

  ffmpeg -re -i fragmentX.mp4 -b:v 118k -b:a 32k -vcodec copy -preset:v veryfast -acodec aac -strict -2 -ac 2 -f mpegts -y fragmentX.ts

  I manage the m3u8 manifest on my own, deleting old fragments and appending new ones.

  When validating the stream, I find it stacked with EXT-X-DISCONTINUITY tags making the stream unwatchable.

  Implementation 2

  First combine latest fragment with overall.mp4

  ffmpeg -i "concat:newfragment.mp4|existing.mp4" -c copy overall.mp4

  Then pass the combination to ffmpeg for HLS segmentation

  ffmpeg -re -i overall.mp4 -ac 2 -r 20 -vcodec libx264 -b:v 318k -preset:v veryfast -acodec aac -strict -2 -b:a 32k -hls_time 2 -hls_list_size 3 -hls_allow_cache 0 -hls_base_url /Users/JosephKalash/Desktop/test/350/ -hls_segment_filename ’350/fragment%03d.ts’ -hls_flags delete_segments 350/index.m3u8

  Concatenation is not perfect and there are noticeable glitches where the fragments are supposed to be stitched. Segmentation replaces older fragments and the manifest is rewritten as if it’s a new HLS stream every time ffmpeg is called.

  I cannot figure out how to get this to work properly.

  Any ideas ?

• HLS implementation with FFmpeg

  10 août 2015, par Joseph K

  I am trying to implement HLS using FFmpeg for transcoding + segmenting but have been facing a couple of issues that have been bugging me for the past week.

  Issue

  Webserver currently receives live MP4 fragments being recorded on-the-go and needs to take care of transcoding and segmentation.

  As mp4 fragments are being received, they need to be encoded. Then segmented. If i run a segmenter (be it ffmpeg or apple mediastreamsegmenter), every mp4 fragment is being treated as a VOD by itself and I’m not being able to integrate them as part of a larger live event implementation.

  I thought of a solution where every time I receive an mp4 fragment, I first use fmpeg to concatenate it with previous ones to form the larger mp4 that I then pass to be segmented for HLS. That did not work either because the entire stream has to be re-segmented each and every time and existing TS fragments replaced by new ones that are similar yet shifted in time.

  Implementation 1

  ffmpeg -re -i fragmentX.mp4 -b:v 118k -b:a 32k -vcodec copy -preset:v veryfast -acodec aac -strict -2 -ac 2 -f mpegts -y fragmentX.ts

  I manage the m3u8 manifest on my own, deleting old fragments and appending new ones.

  When validating the stream, I find it stacked with EXT-X-DISCONTINUITY tags making the stream unwatchable.

  Implementation 2

  First combine latest fragment with overall.mp4

  ffmpeg -i "concat:newfragment.mp4|existing.mp4" -c copy overall.mp4

  Then pass the combination to ffmpeg for HLS segmentation

  ffmpeg -re -i overall.mp4 -ac 2 -r 20 -vcodec libx264 -b:v 318k -preset:v veryfast -acodec aac -strict -2 -b:a 32k -hls_time 2 -hls_list_size 3 -hls_allow_cache 0 -hls_base_url /Users/JosephKalash/Desktop/test/350/ -hls_segment_filename ’350/fragment%03d.ts’ -hls_flags delete_segments 350/index.m3u8

  Concatenation is not perfect and there are noticeable glitches where the fragments are supposed to be stitched. Segmentation replaces older fragments and the manifest is rewritten as if it’s a new HLS stream every time ffmpeg is called.

  I cannot figure out how to get this to work properly.

  Any ideas ?

• Cannot suppress ffmpeg output from ruby

  3 avril 2014, par Danny

  I have ruby on rails app that allows users to upload videos. When a video is added, I have a before_save filter that uses ffmpeg to generate a series of thumbnails. The problem is that ffmpeg is producing tons of console output when I'm saving a video item in the rails console, and when I run my tests.

  My environment :

  • Host Machine : OS X 10.9.2
  • Vagrant Box : Ubuntu 10.04.4
  • ffmpeg version : SVN-r0.5.9-4:0.5.9-0ubuntu0.10.04.3
  • ruby version : 1.9.3-p194

  Command I'm running :

  `ffmpeg -v 0 -ss #{timestamp} -i #{video_file.path} -y -f image2 -vcodec mjpeg -vframes 1 -s 640*360 #{thumbnail_path}/thumbnail#{i}.jpg`

  This version of ffmpeg on my VM doesn't seem to care about the "-v 0" option. I've also tried "-loglevel quiet" which causes ffmpeg to error, indicating that the option isn't recognized (both loglevel and v work on my host machine's ffmpeg).

  Tried using both exec() and system(), which both caused execution to hang. Tried to redirecting output to a file by doing :

  `ffmpeg -v 0 -ss #{timestamp} -i #{video_file.path} -y -f image2 -vcodec mjpeg -vframes 1 -s 640*360 #{thumbnail_path}/thumbnail#{i}.jpg > #{thumbnail_path}/output.txt`

  Still see output. Next I tried :

  `ffmpeg -v 0 -ss #{timestamp} -i #{video_file.path} -y -f image2 -vcodec mjpeg -vframes 1 -s 640*360 #{thumbnail_path}/thumbnail#{i}.jpg &> dev/null`

  Still seeing output ! Finally I tried :

  $stdout.reopen("#{thumbnail_path}/output.txt", "w")
  
  $stderr.reopen("#{thumbnail_path}/error.txt", "w")
  
  `ffmpeg -v 0 -ss #{timestamp} -i #{video_file.path} -y -f image2 -vcodec mjpeg -vframes 1 -s 640*360 #{thumbnail_path}/thumbnail#{i}.jpg`
  
  $stdout = STDOUT
  
  $stderr = STDERR

  Holy cow, that worked ! Well, sort of. No more verbose output when running tests, BUT somehow anytime this runs I get kicked out of the rails console.

  Does anyone have a more elegant solution ?