Signed-off-by: Felix Paul Kühne <fkuehne@videolan.org>

First for the "a=lang:" session attribute, then for each subsession
look for the same attribute, and use the session attribute if none
was found.
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

SET_ES_FMT recreates decoders and then triggers preroll.

Prevents creating ES & decoders just for playlist preparsing.

Also cleans seekpoints between tracks

icu-config is not suited for cross-compilation

People do not read that far and keep asking for support anyway.

Provide a description of the codec if possible
Give a more descriptive message if the codec is "undf"
That one means that the demuxer could not identify the codec

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

Close #10127