[FFmpeg-user] Strange CPU usage in MPEG2 encoding
Roberto Ragusa
mail at robertoragusa.it
Sun Sep 7 14:46:30 CEST 2014
On 09/04/2014 12:33 PM, SF wrote:
> Clearly, the following options :
>
> -b:v 2300k -maxrate 2500k -bufsize 2500k -muxrate 2500k
>
> are consuming more than twice CPU power than
> -maxrate 2500k -bufsize 2500k -muxrate 2500k
What is the resulting bitrate in the second case? Much smaller?
Another explanation could be that if you ask for a very
specific bitrate the encoding process has to encode a frame,
then retry a few times with stronger/weaker quantization to
match the bitrate target. I suppose the code does not
really encode, just estimate used bits, but I would not be
surprised if estimation would be almost as slow as actual
encoding.
I'm not familiar with code internals, so I could be wrong.
--
Roberto Ragusa mail at robertoragusa.it
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