[FFmpeg-trac] #7142(undetermined:new): Not stable fps in delivery rtmp stream
FFmpeg
trac at avcodec.org
Tue Apr 17 14:47:18 EEST 2018
#7142: Not stable fps in delivery rtmp stream
-------------------------------------+-------------------------------------
Reporter: | Type: defect
pavel.khilko | Priority: important
Status: new | Version: 3.4
Component: | Blocked By:
undetermined | Reproduced by developer: 0
Keywords: fps |
Blocking: |
Analyzed by developer: 0 |
-------------------------------------+-------------------------------------
Summary of the bug:
When flipping a thread with a given fps using the -vf "fps = 30" filter at
the output when delivered, the value of fps fluctuates from 20 to 50-60
peaks.
The delivery of frames is controlled by ffprobe, which displays video
frames and the code on JS counts the number of frames that came in a
second.
This behavior is observed only with non-stable input stream, provided
uniform and stable flow of this problem at the output ffmpeg is not
observed.
Also, if we analyze Freeman by comparing the pkt_pts_time of received
frames, the value of fps remains stable and equal to 30, as specified in
the command.
For video analysis, use the module "video-quality-tools"
How to reproduce:
- Emulate the incoming stream with delays in delivery
- Accept ffmpeg input at this prompt
- Output stream also will not have stable fps
{{{
% ffmpeg -i rtmp://localhost/myapp/myStream -s 1280x720 -aspect 16:9 \
-c:a aac -b:a 64k -ac 2 -ar 44100 -c:v libx264 -b:v 1500k -minrate 1500k \
-maxrate 1500k -bufsize 700k -profile:v main -level 4.0 -vf
"fps=30,format=yuv420p" \
-x264opts "keyint=60:min-keyint=60:no-scenecut" -preset veryfast \
-tune zerolatency -threads 0 -f flv rtmp://localhost/myapp/myStream1
ffmpeg version 3.4.2 Copyright (c) 2000-2018 the FFmpeg developers
built with gcc 5.4.0 (Ubuntu 5.4.0-6ubuntu1~16.04.9) 20160609
}}}
Patches should be submitted to the ffmpeg-devel mailing list and not this
bug tracker.
--
Ticket URL: <https://trac.ffmpeg.org/ticket/7142>
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