[mythtv] mplayer + nuv/(mpeg4|rtjpeg) patch

[Isaac Richards]

On Friday 04 April 2003 10:43 am, Geoffrey Hausheer wrote:
> On a similar topic, any idea how difficult it would be to make mencoder
> WRITE nuv files (likely only MPEG4 would be needed)?
> I've been working on coding a transcoder into myth so i can record
> initially in RTJPEG, and transcode to MPEG4, to get a high-quality
> encoding at high resolution with multiple imputs without swamping my poor
> CPU.
>
> Unfortunately, the encoders/decoders in myth are not really designed for
> this.  I can extract the audio/video and write it to a file in
> uncompressed format (by adding some hacks to libmythtv) (I think...i have
> no idea how to actually display the raw data), but I haven't figured out
> how the encoder works well enough to maintain sync, and write a valid nuv
> file.  The encoder in myth is also heavily threaded, which is really not
> necessary for transcoding, since runtime is irrelevant.  I looked at how
> ffmpeg does it, and it is pretty straight forward (decode a frame,
> process frame, encode frame...there is some code to sync video to audio,
> but it is not bad).

If you're just going to do straight transcoding from rtjpeg to mpeg4 and 
keeping things in the .nuv format, this can be done quite easily within 
libmythtv -- see the commented out ReencodeFile() function in 
NuppelVideoPlayer.  It's using an older version of the libavcodec API so 
would need to be updated, and it'll also need to be updated to handle the 
newer modified .nuv file format I'm using.  But, should be pretty easy to 
update it.  You don't need to worry about a/v sync at all, since you'd just 
be doing a straight copy, aside from transforming the video frames into 
another format and updating the appropriate headers.

Isaac