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• HLS with FFmpeg (separated track sync)

  30 janvier 2019, par PhilG

  I’m looking for a solution to proceed transcoding a video file to HLS multi-bitrate with audio track separated

  basically,
  I got a video file, I transcoded it into 4 resolutions + 1 audio track

  • 180p
  • 360p
  • 720p
  • 1080p
  • 2160p (maybe)
  • Audio1
  • Audio2 (maybe)

  but for the exemple, here is my 180p command :

  ffmpeg -i ${source} \
  
      -pix_fmt yuv420p \
  
      -c:v libx264 \
  
      -b:v 230k -minrate:v 230k -maxrate:v 230k -bufsize:v 200k \
  
      -profile:v baseline -level 3.0 \
  
      -x264opts scenecut=0:keyint=75:min-keyint=75 \
  
      -hls_time 3 \
  
      -hls_playlist_type vod \
  
      -r 25 \
  
      -vf scale=w=320:h=180:force_original_aspect_ratio=decrease \
  
      -an \
  
      -f hls \
  
      -hls_segment_filename ../OUT/${base_name}/180p/180p_%06d.ts ../OUT/${base_name}/180p/180p.m3u8

  and the audio track :

  ffmpeg -i ${source} \
  
      -vn \
  
      -c:a aac \
  
      -b:a 128k \
  
      -ar:a 48000 \
  
      -ac:a 2 \
  
      -hls_time 3 \
  
      -hls_playlist_type vod \
  
      -hls_segment_filename ../OUT/${base_name}/audio1/audio1_%06d.ts ../OUT/${base_name}/audio1/audio1.m3u8

  for convenient reason, I launch separate ffmpeg command for each resolution, depending on the video source quality

  Then I create a standard Master Playlist

  #EXTM3U
  
  #EXT-X-VERSION:3
  
  #EXT-X-STREAM-INF:BANDWIDTH=230000,RESOLUTION=320x180,CODECS="avc1.42001e"
  
  180p/180p.m3u8
  
  #EXT-X-STREAM-INF:BANDWIDTH=600000,RESOLUTION=640x360,CODECS="avc1.42e00a"
  
  360p/360p.m3u8
  
  #EXT-X-STREAM-INF:BANDWIDTH=3150000,RESOLUTION=1280x720,CODECS="avc1.4d0028"
  
  720p/720p.m3u8
  
  #EXT-X-STREAM-INF:BANDWIDTH=5000000,RESOLUTION=1920x1080,CODECS="avc1.4d0029"
  
  1080p/1080p.m3u8
  
  #EXT-X-STREAM-INF:BANDWIDTH=128000,CODECS="mp4a.40.2"
  
  audio1/audio1.m3u8

  When I try to read the Master Playlist,
  I don’t have any sound
  Using VLC, the audio track is played before the video tracks

  So, How Can I sync Audio track with Video Tracks ?

  Thanks

• FFMPEG UDP MPEG2TS to Cable TV Channel - Video & Audio Problems

  30 janvier 2019, par user2884023

  Channel Feed Distored Picture

  $ ffmpeg
  
  -re
  
  -i playlist1.txt
  
  -b:v 15000k 
  
  -bufsize 15000k
  
  -maxrate 16000k
  
  -f mpegts "udp://XXX.XXX.X.XXX:XXXX"

  I have mpeg2.ts files encoded to CBR15mbs.
  The files are set to different frame rates. Although initial testing was just playing 1 file.
  They are currently 1080p I think without declaring the frame rate, they are defaulting to 30fps.
  From the server locally via Port2 (that we are using to send our feed), everything plays fine via FFPLAY.
  The final out put local CATV is pixelated and distorted, the video is missing data playing slowly and the audio is choppy / distorted.
  I even tried just a 192kps .mp2 and it played distorted on the CATV channel.
  They set me up with a cable modem. 2 ports, 1 WAN, 1 a dedicated port to feed their head end and I have a fiber synchronous 20/20 connection.

  I am guessing its a packet issue, perhaps on our end with our FFMPEG setup ? And maybe FFPLAY isn’t as sensitive to the actual distro process.

  Perhaps the secret lies here, but there isn’t much info about them, even scouring the net.

  ?pkt_size=188&buffer_size=65535

  For example what is this one :

  broadcast=1|0

  Explicitly allow or disallow UDP broadcasting.

  I apologize if data is missing, please ask questions. I didn’t want to write a novel.

  I am hoping some can provide the correct code so my signal is corrected. I assume the problem is on our end, and not the CATV end. At least I can try some solutions on our end first. I can make real-time FFMPEG changes to the server, and see the channel results instantly so that helps.

  Finally, the fact it wouldn’t even play a .mp2 audio file cleanly on the channel, does make me wonder, is there a problem on their end, or is it a config on our end, and we just need the correct answer ?

• Ffmpeg converting to HLS - video extremely low quality

  7 janvier 2019, par John Kim

  I’m building a streaming webapp that uses FFMPEG. The client sends webcam video using FFMPEG (converting the webm stream into mpeg-ts in the process) over RTMP, and the media server receives the mpeg-ts stream, transcodes it into HLS with multiple quality levels for ABR (using a master playlist).

  So far, I’ve got all of this working, except that my transcoding command creates HLS segments that are extremely low quality ; the video is very pixellated, and the best quality level (1080p) just looks like 240p scaled up to 1080p. In order to test my FFMPEG command I remuxed a sample high quality 1080p movie into mpeg-ts (I checked the quality, it looks the same as the original), and I’m using this command to transcode this movie into HLS for the test :

  ffmpeg.exe -threads 4 -filter_complex_threads 4 -vsync 1 -i output.ts -filter_complex 
  
  "[v:0]split=5[s0][s1][s2][s3][s4]; 
  
  [s0]scale=w=1920:h=1080:flags=lanczos,yadif[v0];
  
  [s1]scale=w=1280:h=720:flags=lanczos,yadif[v1];
  
  [s2]scale=w=854:h=480:flags=lanczos,yadif[v2];
  
  [s3]scale=w=480:h=360:flags=lanczos,yadif[v3];
  
  [s4]scale=w=426:h=240:flags=lanczos,yadif[v4]" 
  
  -map "[v0]" -pix_fmt yuv420p -r 23.976 -vcodec libx264 -b:v 3400k -preset medium -profile:v baseline -keyint_min 24 -g 48 -x264opts no-scenecut -strict experimental -map_metadata -1 
  
  -map "[v1]" -pix_fmt yuv420p -r 23.976 -vcodec libx264 -b:v 1725k -preset medium -profile:v baseline -keyint_min 24 -g 48 -x264opts no-scenecut -strict experimental -map_metadata -1 
  
  -map "[v2]" -pix_fmt yuv420p -r 23.976 -vcodec libx264 -b:v 960k -preset medium -profile:v baseline -keyint_min 24 -g 48 -x264opts no-scenecut -strict experimental -map_metadata -1 
  
  -map "[v3]" -pix_fmt yuv420p -r 23.976 -vcodec libx264 -b:v 510k -preset medium -profile:v baseline -keyint_min 24 -g 48 -x264opts no-scenecut -strict experimental -map_metadata -1  
  
  -map "[v4]" -pix_fmt yuv420p -r 23.976 -vcodec libx264 -b:v 320k -preset medium -profile:v baseline -keyint_min 24 -g 48 -x264opts no-scenecut -strict experimental -map_metadata -1 
  
  -map a:0 -map a:0 -map a:0 -map a:0 -map a:0 -c:a aac -b:a 96k -af “aresample=async=1:min_hard_comp=0.100000:first_pts=0” 
  
  -f hls -var_stream_map "v:0,a:0 v:1,a:1, v:2,a:2, v:3,a:3, v:4,a:4" 
  
  -hls_wrap 24 -hls_time 10 -master_pl_name master.m3u8 "C:/Users/John/Desktop/ffmpeg-20181218-978c935-win64-static/bin/vs%v/manifest.m3u8"

  I’m very new to FFMPEG, I referred to this article for the video options, and modified it to create HLS instead of mp4. Needless to say I botched this up pretty bad, although the command itself works and does what I need it to (other than the crappy quality). Could anyone help me optimize this command to make it transcode much less lossy video ?