CBR export ignores bitrates set in Adobe Premiere

[nicos23598923]

Hi folks,

I have the problem that doing an export I set appropriate levels (5.2) and profile (high). Output Format is H.264, source is also H.264.

Using CBR export I choose 100 MBits as the source content also provides this bitrate.

Whatever I'm doing - the resulting output bitrate is always around 35 MBit and the resulting output file is (of course) much smaller than the original files.

I found other posts regarding this topic, but no written solution to this behaviour. Can anoybody give me a hint what to do to get my export with the desired bitrate?

Cheers,

Nico

[nicos23598923 · Accepted solution]

I finally found out what's helping here.

I'm currently working with an mobile computer equipped with an integrated Intel graphics card.

Switching from hardware-accelerated export to software in the export screen fixed this issue.

Cheers,

Nico

[R Neil Haugen]

The reason this happens is because in "hardware" H.264 exports, the computer's CPU hardware for H.264 work is used to do the encode ... so it does the encode as it's setup to work. For "software" encoding for H.264, Premiere is handling the encdode process through the CPU "personally". And follows your settings.

Neil

[RjL190365]

In addition to the above replies, your settings exceeded the hard-coded maximum bitrate limit of hardware encoding for all H.264 exports. The absolute maximum that's allowed for hardware encoding is between 50 and 60 Mbps. Setting too high of a bitrate will default your hardware H.264 encodes to a fail-safe rate of only 35 Mbps for 4k or 16 Mbps for 1080i/p.

What's more, Adobe does not currently support smart rendering for H.264 at all. Smart rendering is supported only for certain intermediate codecs, but not for H.264 or HEVC. Thus, Premiere Pro's H.264 and HEVC encoders will always re-encode everything no matter what.

[nicos23598923]

Thanks - your feedback is greatly appreciated and valuable! As my source is already H.264 and not ProRes or other supported formats Smart Rendering is sadly not an option for my footage. Should I ever swap my aircraft (I'm doing drone footage) to anything that supports ProRes nativly (like the Mavic 3) that woulde be an option.

Due to my target being mostly YouTube high bitrates are questionable. Setting the export options to CBR 45 MBit/s work together with hardware acceleration. I'm able to push this up until  60 MBit/s. Anything above this value won't work with hardware acceleration.

So sticking with 45 MBit/s seems the sweet spot, at least accoding to the official recommendations of YouTube.

[R Neil Haugen]

One thing that I know a number of higher-end video post folks do with YouTube ... they'll take DNx and ProRes I think both ... and getting the upload in those seems to  get around some of the worst potential re-encoding artifacting.

Longer uploads, of course.

And having RJL190365 on this forum is a HUGE help to all of us.

Neil