[MPlayer-dev-eng] [PATCH] Add "lpcJ" fourcc to codecs.conf

[Francesco Lavra]

On Sun, 2010-05-02 at 15:34 -0400, compn wrote:
> On Sun, 02 May 2010 16:33:39 +0200, Francesco Lavra wrote:
> >On Sun, 2010-05-02 at 14:08 +0000, Carl Eugen Hoyos wrote:
> >> Francesco Lavra <francescolavra <at> interfree.it> writes:
> >> 
> >> > $subj, "lpcJ" is a valid fourcc for the RealAudio 1.0 codec.
> >> 
> >> Please point us to a sample and I will apply.
> >
> >If/when the just submitted patch series for the FFmpeg RM muxer will be
> >applied, samples can be created with FFmpeg.
> >If I have to wait until then, well, I don't mind :)
> 
> does realplayer handle those 1pcJ files ? is there a difference in the
> codec/bitstream in 14_4 vs 1pcJ ? if not, why not just keep 14_4 and
> abandon 1pcJ (in the encoder patch) ?
> 
> this codecs.conf entry seems fine to me as long as 1pcJ is an actual
> fourcc found in the wild.

Realplayer plays those lpcJ files flawlessly.
There is no difference in the bitstream between between 14_4 and lpcJ.
But it would make more sense to drop the 14_4 tag in favor of lpcJ,
since all samples that I found in the wild (including those in
mplayerhq.hu) have lpcJ tag, not 14_4.
The reason why the samples play with the unpatched mplayer is that the
realmedia demuxer does not read the fourcc contained in the samples, and
mplayer fills the codec_tag field based on its own tag lists.
With the changes to the realmedia muxer that I'm proposing on the ffmpeg
list, the format of the created samples is different in that it contains
additional headers, from which the demuxer is able to get the codec tag;
if the codec tag is obtained from the demuxer, mplayer doesn't use its
own tag lists, and that causes it to fail.