[MPlayer-users] Mencoder: are the displayed bitrates accurate?

[Levente Novák]

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>Of course. A bitRATE is a rate, which means it involves bits and time.
>MEncoder's numbers are for the whole file, i.e. total bits/total time.
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Yes, I understand what a rate is, but a frame can also have a bitrate: 
the number of bits sent per the duration of the frame. And sadly enough, 
standalone DVD or VCD players do not care about averaged bitrate (so 
that mencoder displayed values are maybe not totally useless, but close 
enough in this case), they expect a certain maxrate to be meet. If you 
have a higher bitrate even for only one frame, the player won't play it.

In my opinion (but AFAIK this is shared by many others), mencoder is 
close to useless in producing streams for DVD or (S)VCD authoring if it 
is impossible to set a maxrate lock. It would be a pity since its 
quality, speed and the number of postprocessing options should make it 
the best encoder out there.

>Computing a bitrate for a single frame is very silly, since obviously
>some frames will take many more bits (easily up to 100x more) to
>encode than others.
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It is not silly at all. If you have to set a maximal rate, these frames 
should be quantized with higher value quantizers then, but it should not 
exceed the maxrate. It is mandatory in many cases, otherwise the DVD or 
CD won't play in a standalone player.

Levente