MP4 bitrate capping


When compressing the video in MP4, it would be great to cap the video bitrate.
For instance, I have set compression factor of 15, and the average bitrate is 30MBps.
But, it happened to bump to 60 or even 84MBps once in this video.

If we want to make a Blu-Ray-compliant video, capping the bitrate to 40MBps would be a good idea.


So right now they use CRF which is generally the best bitrate control mode for h264/h265. The problem is you have no guarantee the bitrate conforms to blu-ray standards which are quite strict. Topaz also is using x264 as the transcoder. I checked with mediainfo on a test output and they aren’t setting blu-ray compatibility
nr=0 / decimate=1 / interlaced=0 / **bluray_compat=0** / constrained_intra=0 / bframes=0 / weightp=0 / keyint=12 / keyint_min=1 /

The audio is also transcoded as 96kbit aac-lc. Which is on the low end of quality for AAC, probably sounds like a160kbit mp3. It also transcodes the audio regardless of the original format which could reduce the quality.

I think it would be better to output as prores and then transcode with a blu-ray preset on something like premiere or x264 manually.

These are really usefull infos, thanks a lot!

However, it would be great to include more options to the MP4 encoding within VEAI.

I will explore the ProRes => ffmpeg x286 solution in the meantime.

It would be very convenient but imagine how much effort it would be to add all the options for x264 transcoding, probably have some profile selector where you can pick “blu-ray”. On the other hand they could continue work on improving the primary function of noise reduction/upscaling. Honestly I think they should just offer prores, tiff 8/16, and png. I was also going to put a feature request in for UT video support so there was a lossless video output.

They can’t implement all options for sure!
But a bit more options than just the CRF option would be enough.
However, removing video compression feature for h264 is not a good idea because not user friendly.