[FFmpeg-user] HTTP playlist stream copy to an IP QAM modulator
anacelia.sarlo at gmail.com
Wed Jul 20 04:16:03 EEST 2016
I'am receiving an HTTP playlist stream (.m3u8 with H.264/AAC
elementary streams) and want to do a stream copy (no transcoding) and mux
output with mpeg-ts format, ideally in real time. This output is received
by an IP QAM modulator and then distributed to the cable network (DVB).
This is the ffmpeg command :
ffmpeg -re -y -i $stream -c copy -f mpegts -map 0:0 -map 0:1
-mpegts_pmt_start_pid 66 -streamid 1:71 -streamid 0:70 udp://
When I watch the stream from the cable network, the audio is OK but the
video looks sometimes faltering and other times too fast, and out of sync.
But when I received this same output with ffplay it runs OK.
It seems there is a problem with the time base, I did many testings with
(genpts, copyts, etc) with no good results.
The IP QAM provider said that it can receive a variable bit rate stream,
but I heard that most IP QAMs works just with constant bit rates.
I have the following questions :
1. Does the ffmpeg command is correct for my intention ?
2. In case I have to generate a constant bit rate, how can I do that ? is
it necessary to transcode ?
Thanks for any suggestions!
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