[mythtv] LAME is mandatory?

[Colin Guthrie]

Janne Grunau wrote:
> NuppelVideoRecorder is the main class that uses LAME for MP3 encoding. 
> Removing LAME will result software capturing and transcoding only 
> supporting WAV audio, which makes them imho useless.

Perhaps yes. Still tho' it wouldn't make MythTV useless as a whole -
e.g. for DVB users etc.

I don't know much about the nuppel format but is MP3 the only supported
codec? Could it instead be patched to compress to another, more open
format e.g. vorbis? (this is a "is it possible" rather than "will
someone do it" question ;))

>> I guess the ultimate solution would be for ffmpeg to integrate MAD
>> decoding and LAME encoding/decoding and make each optional. Perhaps
>> it does have multiple MP3 decoders that I don't know about (not spent
>> too much time learning) and it only really uses LAME for encoding
>> anyway.
> 
> libavcodec has a native MP3 decoder.

This is good. Thanks for filling the knowledge gap :) This should mean
that the Anssi's original patch that added MAD support doesn't need to
be as complicated. Which is what I've done in my update to it.

In my update the nuppelvideodecoder.{h,cpp} files are untouched. This
should mean it can decode/play mp3 encoded files even if the recorder
cannot record to them (as from what little time I spent looking at the
code, it appears to just use libavcodec/ffmpeg for the decoding now
rather than lame directly as was the case in 0.20.

> faad is optional and not enabled by default but ffmpeg may have a native 
> decoder in a couple of weeks. Disabling codecs or formats should work 
> the same way as in ffmpeg. The configure script knows the same options 
> but using them is not actively supported.

OK thanks. I guess some hard coded assumptions of lame being available
are in other parts outside of libavcodec tho' and the libavcodec.pro
file is presumably custom to Myth? I've upload the revised patch to
ticket #3233 if anyone cares to look but I appreciate now that this is
not a huge priority for upstream - it will hopefully help some packagers
tho' :)


Col


-- 

+------------------------+
|     Colin Guthrie      |
+------------------------+
| myth(at)colin.guthr.ie |
| http://colin.guthr.ie/ |
+------------------------+