[streaming] Re: Aspect ratio change not preserved when transcoding

[Bjørn Olav Ruud]

For those interested, I now have hosting for two test TS files at:

ftp://82.117.42.160/

The file nrk1-169-43-169lowres.ts starts as 16:9, changes to 4:3, and
ends with 16:9 in reduced resolution. Playing the files normally works
as intended. When transcoding the initial aspect ratio never changes,
and the resolution change at the end corrupts the image. I created a
multicast stream for testing with the following command:

vlc \
--color \
--extraintf logger \
-vvv \
--ttl 12 file:///home/bjorn/nrk1-169-43-169lowres.ts \
--sout '#transcode{vcodec=mp4v,vb=2000,deinterlace}:std{access=udp,mux=ts,url=239.192.0.63}'
\
--udp-caching 10000 \


On 1/3/07, Bjørn Olav Ruud <bjorn.ruud at gmail.com> wrote:
> I have a multicast stream in raw UDP MPEG TS (MPEG-2 video, layer 2
> audio) as input, which is transcoded to MPEG-4 video and sent back out
> as a new multicast stream. This is the sout command used with VLC
> 0.8.6 on Gentoo Linux:
>
> '#transcode{vcodec=mp4v,vb=2000,deinterlace}:std{access=udp,mux=ts,url=239.192.0.63}'
>
> The input stream has both 4:3 and 16:9 material, and on occasion sends
> material in reduced resolution (544x576, both 4:3 and 16:9 DAR).
> Aspect and resolution switching works fine if the original TS is
> played back, both as a stream and as a file. If the stream is
> transcoded, the aspect ratio information seems to be lost. The output
> stream gets an initial aspect and never changes. If a resolution
> change occurs the image gets corrupted.
>
> Does anyone have a solution for this?
>
> I have a sample that starts as 16:9, changes to 4:3, and finally to
> 16:9 with a reduced source resolution. The file is rather large at 72
> MB, so I don't have an immediate way of hosting it. Let me know if
> anyone wants it uploaded somewhere.
>
>
> Regards,
> Bjorn Ruud
>