[Ffmpeg-devel] Re: Problems encoding H264 with a MP4 / MOV container with ffmpeg

[Tuukka Toivonen]

On Fri, 17 Jun 2005, Bill May wrote:

>> On the complete same machine I can encode to mpeg4 720x576 in realtime
>> (+audio and filtering). Using h264 that goes down to 360x288 (x4
>> slowdown!), not quite usable. I hope that's not inherent to the encoder!
> H.264 is a lot more CPU intensive.  The fact that we can do live encoding
> at all (even at CIF) so soon after the spec is "finalized" is pretty
> amazing.  With mpeg-4, it took many more years.

Also, more compression -> more CPU power required. Which means
that if you aren't trying to get much compression with H.264,
it will be much faster (in the extreme case, no motion estimation, no 
intelligent mode selection).

I wouldn't be surprised if H.264 wouldn't require more CPU than
MPEG-4 at the same compression levels, but with H.264 one is just able 
to do so much more coding decisions.