[MEncoder-users] many mencoder questions from a newbie

[belcampo]

On 12/19/2011 11:58 PM, Janos Szamosfalvi wrote:
> --- On Mon, 12/19/11, belcampo<belcampo at zonnet.nl>  wrote:
>
>> Partly answer, first you may check if your tablet is able
>> to play  HighProfile files. The HighProfile 8x8dct:bframes=3
>> mightgive you troubles.
>> Further you might try crf=20 instead of
>> bitrate=1500:vbv_maxrate=1600
>> crf takes the amount of bits it needs for "quality 20".
>> Your quality comes at QP:13.43 and QP:17.15 for I and P frames,
>> this is somewhat high. Where lower numbers mean higher quality.
>> Maybe it's something to  start with.
>
> I specified bitrate and not 'crf' because as per documentation
> for "pass=<1−3>":
>
> "The first pass may use either average bitrate or constant
> quantizer.  ABR is recommended, since it does not require
> guessing a quantizer. Subsequent passes are ABR,
> and must specify bitrate."
Multipass makes only and ONLY sense if you need max quality for a given 
size. This means if 1-5% more or less size doesn't matter that much, you 
can forget all the multi-pass. It's a waste of time. Quality as an 
absolute value doesn't improve. Maybe filesize is a litle less.
Try some single and multi-pass encodings and compare the results, you 
then can decide if the few bytes smaller size are worth the extra time 
needed for the encoding.
> ------------------------
>
> In addition, bitrate is something I know and can check with
> gspot or mediainfo and can easily compare to other files.
>
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