[FFmpeg-user] Howto specify needed options for ffmpeg

Carl Eugen Hoyos ceffmpeg at gmail.com
Thu Sep 24 19:20:07 EEST 2020


Am Do., 24. Sept. 2020 um 16:18 Uhr schrieb Thomas Seilund via
ffmpeg-user <ffmpeg-user at ffmpeg.org>:
>
>
> On 9/23/20 10:42 PM, Carl Eugen Hoyos wrote:
> > Am Mi., 23. Sept. 2020 um 17:24 Uhr schrieb Thomas Seilund via
> > ffmpeg-user <ffmpeg-user at ffmpeg.org>:
> >
> >> Now I write to udp and not to a local file with this command:
> >>
> >> raspivid -t 0 -b 10000000 -n -o udp://239.255.42.42:5004
> >> Connecting to 239.255.42.42:5004...connected, sending video...
> >>
> >>
> >> On the same host I read from udp with this command - video is never
> >> displayed
> >>
> >> ffplay -f h264 -i udp://239.255.42.42:5004
> > In general, you should not force the input format.
> >
> > You should be able to record the udp stream with tcpdump,
> > you can then investigate the output file.
>
> I will try to investigate. It was my idea to force the input format.

As you found out, this is not possible to the extent you wanted.

> How come that is not a good idea?

You may receive a different stream than what you expect, the
auto-detection is meant to be very reliable.
(This does not mean it cannot fail but you cannot work-around
the issues you see with forcing the format.)

> >> ffplay version N-97152-g52523b6963 Copyright (c) 2003-2020 the FFmpeg
> >> developers built with gcc 8 (Raspbian 8.3.0-6+rpi1)
> >>    configuration: --extra-libs='-lpthread -lm' --enable-gpl
> >> --enable-libass --enable-libfreetype --enable-libmp3lame
> >> --enable-libvorbis --enable-libx264 --disable-doc --enable-nonfree
> > Is this binary distributed somewhere?
> I used apt-get install on Raspberry Pi.

Where can I find the repository where you download this
binary? Providing this binary for download is not allowed.

Carl Eugen


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