I’m searching for a way to encode a file for best possible constant quality, based on a specific size.

I was wondering if there was a way to tell an encoder to CRF up to the credits (specifiying a specific frame), at which point the credits are encoded using two pass to achieve an overall average bitrate, acknowledging the size of the CRF encoded portion as well.

You would set a minimum bitrate so that the credits weren’t totally botched. The encoder would look at the CRF portion, then see if the credits could be encoded at the minimum bitrate to reach the desired size. If not, the encoder would repeat the CRF encode at one value lower, and repeat the process. Otherwise, the two pass would be completed on the credits to allow for potentially better quality

All of you scripters… has this been done, or is there any way that you could look into a way to do this for mpeg2 and h.264?