demux_lavf: assume audio codec_tag 0 means unset

Libavformat does not distinguish between "no codec_tag given" and
"codec_tag given, value is 0". 0 can be a valid value. Change
demux_lavf to assume that 0 always means unset for audio. This
prevents incorrect selection of the PCM decoder, which includes
"format 0x0" in its codecs.conf entry. The video case accepts 0 iff
codec_id is RAWVIDEO, but there's no obvious similar check possible
for audio. Thus this could possibly cause issues if a file really uses
0 to mean uncompressed audio.

0 files changed, 0 insertions, 0 deletions