Does GMC and bframes slow down playback?

[Snilly]

Howdy,

I think we can all agree that the encoding process is slower with GMC and/or bframes swiched on. What I'd like to know is after reading few a through threads some people are saying that the completed AVI file requires significantly more CPU usage to playback if you encoded with GMC and/or bframes.


Can those affected please tell us what they have seen? I'd really like to know if the use of GMC does anything at all(apart from slowing down encoding and now potentially playback too!).

Snilly :sly:

[mtrooper]

b-frames slow playback down (at least in my experience), BUT only if you're wathing AVI/ogg file. If you use MP4 file (convert AVI with CBR MP3 (not muexed with Nandub, you must mux "riff'ed" mp3 with VDub), then 640x480 movie will playback without problems even on p3 500@515 with GeForce 2 MX400, 256 ram running WinXP Pro.
The reason that it plays much better is because MP4 files are better suited for MPEG4 video (at least that how people expalined to me...)

But I don't think that GMC should slowdown playback (after all, it's "only" intelligent motion detection mechanism, if I'm not mistaken).

And another thing: It may be that QPel slows decoding down A LOT! At least so it seems to me: encoded a movie with B-frames and GMC, no QPel, res. was 640x3XX (PAL), muxed it in .ogm and it plays back just fine on above mentioned PC...

Conclusion: If you have a huge res. (read width>640), use MP4 (if you don't have time/resources to test on a relativly slow PC).

[pcsl999]

Please read this

http://forum.doom9.org/showthread.php?s=&threadid=19426

[Snilly]

Hmm nice job, seems to indicate though that bframes does not hinder playback, I thought of any of the three options that would affect playback the most.

Am I just crazy?