HOW TO LIMIT VIDEO BITRATE ON HD PUBLISHING?

[orizaba]

Hi Igor, I have a problem!

I mainly use PTE AV STUDIO PRO 10.0.11 to edit movies, publish respective HD MP4 files, and using other softwares burn respective Blu-ray discs. Blu-ray discs do not allow total bitrate bigger than 48Mbps (with maximum video bitrate 40 Mbps).

My movies are mainly Super8 old movies which I send to Germany for a professional frame by frame wet gate digitalization. I receive my digitized clips as MP4 files around 80 MB each, average video bitrate 60Mbps with peaks around 180Mbps.

After editing in PTE, when publishing at 23000Kbps, HD MP4 files are around 23Mbps average, with peaks around 160Mbps. Neither my media player (POPCORN HOUR A-210) nor my Blu-ray table player can play such files smooth, on the contrary, in bitrate peak points everything freezes.

Question is: is there a way in PTE software to limit video bitrate on publishing MP4 HD files? Or even to use a constant bitrate (around 40-48Mbps) instead of the actual variable bitrate, this way avoiding peaks?

Using "Total Commander" software I tried to look for PTE lines concerning publish steps but I found nothing.

Could you please let me know how to solve this problem?

Regards,

Jose

 

[tom95521]

I was curious about this so I played with encoder-hd.ini (after making a backup of the file).

HW encoding with NVIDIA 1660 Super.

I changed this line
VidCmdLine=-me_method umh -refs 4 -bf 3 -maxrate 30M

and it seems to limit the bitrate to 30 Mbits.

Might not be an Igor approved solution.

Tom

[orizaba]

Hi Tom,

Thanks very much, I will try and let you know.

Regards,

Jose

[tom95521]

Hi Jose,

I'm not an expert at all of the x264 options but it's fun to experiment. If -maxrate is not working then you might try  --vbv-maxrate and --vbx-bufsize instead of -maxrate. It might create other problems like pause in streaming.

--bluray-compat --vbv-maxrate 40000 --vbv-bufsize 30000

from

http://www.x264bluray.com/home/1080i-p

 

Tom

[tom95521]

This is my latest result from testing. I picked a very dynamic video to test. The 10 Mbits can be changed.

VidCmdLine=-me_method umh -refs 4 -bf 3 -b:v 10M -maxrate 10M -bufsize 10M

Info from

https://slhck.info/video/2017/03/01/rate-control.html

YT Video

https://www.youtube.com/watch?v=G65f290UNh4

Tom

YT Video
Original size 23 MB
99.9 Mbit no maxrate size 247 MB
99.9 Mbit 10 Mbit maxrate size 70 MB

Sample Project
99.9 Mbit no maxrate size 474 MB
99.9 Mbit  10 Mbit maxrate size 159 MB
10 Mbit no maxrate size 181 MB
10 Mbit 10 Mbit maxrate size 159 MB

[orizaba]

Hi Tom,

I can see that you have been trying every possible solutions, just like me. I spent last 2 days (fulltime!) trying and testing your suggestions as well as others of my own, but results are zero! I can not imagine what is going on with my PTE project (as normal as usual) because my HD MP4 file (built with bitrate 23000 kbps, as usual) always comes out with average around 23000,  but with some peaks from 50000 to 160000 kbps. Problem is that such amount of high peaks turns the reading impossible on my media player or on Bluray player. So, I could not find a way of getting a constant bitrate of around 30 to 40 kbps, with no peaks at all. A bitrate really constant, not variable.

This morning, googling, I saw that Handbrake software can poduce a real constant bitrate of any value I want. I tried and it really works! And it is very fast. My 30 minutes HD MP4 file (from PTE), takes about 6 minutes to turn it into a MKV file (my choice) with a real constant bitrate 40000 kbps, no peaks at all. So, I solve my problem!

My only concern by now is how such “conversion” is made, having in mind that only 6 minutes is not enough to convert a 30 minutes file. So, what kind of change is made, and how, to “delete” peaks, not changing image quality at all? I should like to know the answer!

Igor said nothing yet but it would be great if PTE could have this option (a real constant bitrate, the way Handbrake uses) when publishing HD MP4 file.

Thanks for your help.

Jose

[tom95521]

Hi Jose,

I agree it would be nice to have more control over h.264 parameters in PTE like in Handbrake for constant bitrate, profile, b-frames,i-frames, etc. If I don't find a suggestion in the Suggestions for Next version I will create one. I'm glad you were able to find a solution. I think most people are happy with CRF and let x264 decide the dynamic bitrate for videos.

I sometimes wonder when a video hesitates that maybe the bitrate is too high or the video buffer is too small. I try to start a video with a black screen for a few seconds so the buffer can fill without pausing the video later.

I just like playing around with settings when I have free time. I think Igor is focusing on the new ARM Mac Mini before beta testing starts.

Thanks,
Tom