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• ffplay got extra delay seconds than ffmpeg

  14 juillet 2017, par jiandingzhe

  I am working on low-latency video streaming. When I was making some tests, I noticed ffplay got much extra latency than ffmpeg, though they are the same software package.

  The video is encoded in H.264, size 320x240, 15fps. The stream is packed in FLV format, uploading and receiving are both done via RTMP. ffmpeg is called fairly simple :

  $ ffmpeg -i 'rtmp://my.path.to/my_rtmp_stream' -f sdl window_title

  And ffplay is also called in simple way :

  $ ffplay 'rtmp://my.path.to/my_rtmp_stream'

  The ffmpeg would starts to show the video instantly, and plays the video with minor latency (<0.5s) ; while ffplay would start the video in 5 seconds, and introduce a delay of 8 seconds.

  I further optimized the ffplay way, by minimizing probe size :

  $ ffplay -probesize 32 'rtmp://my.path.to/my_rtmp_stream'

  In this way, the startup goes quickly, but the delay is still 3 seconds.

  Why they behave so differently ?

• HLS stream created by ffmpeg pauses every 5 seconds

  17 juillet 2017, par megacraft

  I am having problem remuxing an H264/AAC encoded file. There is a file on a server with H264-encoded video with AAC audio (example : input_video.mp4). An I-frame exists every 5 sec video. It is read by ffmpeg splitter/muxer application which splits and muxes it into 5 second video clips and then sends to the client over HLS protocol.

  While playing on client player there is a short pause every 5sec. This issue occurs only when ffmpeg higher than 2.4 is used, so in case ffmpeg pre 2.4.x is used (e.g., 2.0.8) then created video plays just fine.

  I have looked into https://github.com/FFmpeg/FFmpeg/blob/master/Changelog & https://github.com/FFmpeg/FFmpeg/blob/master/doc/APIchanges to spot changes in splitter/muxer but couldn’t find relevant info.

  Please give an answer or hints if you had a similar problem and solved it or have any idea what causes this issue.

• Delay video (and audio) by x seconds in FFMPEG HLS Stream

  2 mai 2023, par Daniel Schmidt

  I have an input HLS stream stream.m3u8 (e.g. using my macbook camera by running ffmpeg -f avfoundation -framerate 30 -i 0 -c:v libx264 -c:a aac -b:a 128k -ac 2 -crf 5 -preset veryfast -hls_time 1 -g 30 -sc_threshold 0 -f hls -hls_init_time 1 -hls_list_size 180 -hls_delete_threshold 180 -hls_flags delete_segments -hls_start_number_source datetime stream.m3u8).

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  I want to use FFMPEG to create another HLS stream stream-60.m3u8 in which the video is delayed by an arbitrary amount of seconds, e.g. 30s.

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  I tried ffmpeg -itsoffset 30 -i ./stream.m3u8 -c copy stream-60.m3u8 but the video delay is around 5s.

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