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I am currently grabbing a live stream video with the following command:

ffmpeg -i https://urlToTheStream/playlist.m3u8 -f image2 -q:v 30 C:\pathToOutputFolder\%01d.bmp

video is running in 24 fps.

I am then live-processing the bmp files with a self written java program. My processing program is a bit faster than the output of ffmpeg. i can see that ffmpeg produces packages of bmp files. Around 25 and then pauses.

Is it possible to tell ffmpeg not to buffer anything and instead just producing "in realtime"?

At first I used jpg format which was clearly slower than bmp. I changed quality to 30 which helped too. But I still have a latency about 0.7 seconds compared watching the stream in the browser. I also tried the no buffering option with no efford.

Thanks for any tips!

edit: code format settings in text

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  • If latency matters to you, you shouldn't use HLS in the first place.
    – Brad
    Commented Mar 22, 2022 at 23:29

1 Answer 1

Reset to default
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ffmpeg -i https://urlToTheStream/playlist.m3u8 -f yuv4mpegpipe -

Read from stdout pipe, The format is documented here https://wiki.multimedia.cx/index.php/YUV4MPEG2

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  • Thanks for the answer. Before I start messing around with piping (I am using Java under Windows) I tried to route the pipe to ffplay to see if lag is less. fmpeg -i https://urlToTheStream/playlist.m3u8 -f yuv4mpegpipe - | ffplay -f rawvideo -pix_fmt yuv420p -s 1440x1080 - encoding seems not quite to function right, i have a shifting picture, but its quite recognizable, that the lag is still there.
    – Che
    Commented Jun 12, 2018 at 11:12
  • You need to force the same format on ffplay, or skip it altogether.
    – Gyan
    Commented Jun 12, 2018 at 19:31
  • @Gyan Thanks for the reply. ffplay doesnt support the yuv4mpegpipe format I think. Do you have a hint for me, what you mean by >forcing or >skipping together ?
    – Che
    Commented Jun 13, 2018 at 7:13
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    ffplay supports everything ffmpeg does. ffmpeg -i https://urlToTheStream/playlist.m3u8 -f yuv4mpegpipe - | ffplay -i -
    – Gyan
    Commented Jun 13, 2018 at 7:29
  • ffmpeg -i https://urlToTheStream/playlist.m3u8 -f yuv4mpegpipe - | ffplay -i - works, but the lag is still around 1 second compared to the video playing in my browser in parallel. image.ibb.co/jietEd/z.jpg See, that the speed should be high enough.
    – Che
    Commented Jun 13, 2018 at 8:29

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