[MPlayer-dev-eng] [PATCH] mencoder, B-frames, and video/audio delay

[Loren Merritt]

On Fri, 20 Jan 2006, Corey Hickey wrote:
> Loren Merritt wrote:
>>>> BTW I think there's a corresponding problem at the _decoder_ end too,
>>>> which you should check out. (Use h264 with deep pyramid to test it..)
>>>
>>> You mean b_pyramid with lots of b_frames? I'm not seeing any problem
>>> here... I tried adding b_pyramid to each of my test clips and they
>>> looked fine (with my wrongly-patched mencoder). The mplayer man page
>>> says b_pyramid "increases decoding delay to 2 frames". If that's the
>>> problem, I don't know if I would notice a 2/24 second delay. Can you
>>> elaborate?
>>
>> Right, x264 doesn't support pyramid with depth > 2.
>> But you can still modify the "delay" header to say 16, even if it only
>> uses 2. (x264/encoder/set.c:187)
>
> I'm confused as to what you two mean by "depth". Do you refer to the
> number of B-frames?

I mean decoding delay.

depth 0: no B-frames.
depth 1: B-frame 1 depends on P-frame 0. (no B-refs)
depth 2: B-frame 1 depends on B-frame 2 depends on P-frame 0.
...

--Loren Merritt