Recode shrink H.264 like DVDs?

[acidsex]

I was sitting here thinkign the other day, any chance we will see Recode with ability to recompress H.264 AVC HD files like they did with DVDs? What I am trying to say is that some of my HD captures are 12Gb and I would like to store them on DVD5 or DVD9 discs yet keep the highest possible quality.

Is there any reason this could not be accomplished in the same way that Recode shrank DVD9 to DVD5?

Im curious to hear thoughts on this.

[nm]

Um, just re-encode with a lower bitrate and/or resolution.

[acidsex]

well, Im looking more along the lines of the speed increase like Recode did with DVDs. I take it this isnt possible.

[DarkZell666]

You're talking about AVC man, no miracle possible :)

[acidsex]

Yeah but AVC is a codec just like Mpeg-2. How was Recode to peel down the bitrate so quickly with Mpeg-2 yet cannot do the same thing with AVC? Not being argumentitive, just trying to understand.

[Sharktooth]

AVC is more complex than MPEG2...
How come that ZIP is faster than RAR? Same thing...

[bobololo]

I guess acidsex is thinking about AVC trans-rating which shouldn't require a complete decoding followed by a full encoding. This is what Recode is doing when it squeezes DVD9 to DVD5 in MPEG-2. In the absolute there is no reason which prevents this to be done with AVC. And if it'd work well it would actually speed up the process.

However it's hard to say if a simple re-quantization process (which is the usual way to trans-rate) can insure a decent coding efficiency without doing some motion refinements and without considering intra predictors. And doing so would ruin the speed gain.

[dragongodz]

I guess acidsex is thinking about AVC trans-rating which shouldn't require a complete decoding followed by a full encoding.
reading his first post i agree, thats what i assume he means aswell. compressed domain transcoding(or transrating).

In the absolute there is no reason which prevents this to be done with AVC.
agree. there is no reason it couldnt be done for AVC just as its also possible to with mpeg 4 part 2 aswell(ie. xvid).
the problem is there really doesnt seem to be anyone interested in doing it. :)

However it's hard to say if a simple re-quantization process (which is the usual way to trans-rate) can insure a decent coding efficiency without doing some motion refinements and without considering intra predictors. And doing so would ruin the speed gain.
requant and dropping of dct coefficients is the usual method. of course this will never be as good as full re-encoding but thats not the point of it. as already proved by mpeg2 CD transcoders you can use this for acceptable results(everyone has their own opinion on what they find acceptable of course).
there are of course other ways to try and improve said results such as motion refinement, strategic requant placement etc etc etc. all of which is outside the bounds of this thread. :)

[Dark Eiri]

This would be a quick way to backup double\triple\+ layer BluRay or HD-DVD to single layer discs. Maybe with the burners coming soon...

[Sharktooth]

AVC support several partitions types... it would be a sub-optimal compression (yes, fast but no good as recompressing).