H.264 Encoding Options: B-Frames

keithm57

Newbie Joined: Dec 07, 2016 09:38 Messages: 8 Offline

Solved by

Sep 20, 2018 14:48

A potential client wants us to use "High profile; two consecutive B-frames" when we produce a video for them. According to Adobe, there are three options to H.264 encoding: I-Frames, P-Frames, and B-Frames. B-Frames are "bi-directional predicted frames...This makes B-frames the most efficient frame of the three." So, I suspect that they compress into smaller files than the I- and P-frames, and maybe my potential client wants the smaller size to load faster online, but it doesn't really matter why.

Question 1) Does anyone know which of these three encoding options PowerDirector (I'm on v.17) uses when it produces an H.264 MP4 video?

Question 2) And what do they mean by "high profile?" That may have nothing to do with B-frames.

I'm having a little trouble figuring out which encoding option Powerdirector uses. If anyone knows the answer to these two questions, or where I can find them, I would appreciate the help!

Thanks,
Keith

PowerDirector Moderator

Senior Contributor Location: New Taipei City, Taiwan Joined: Oct 18, 2016 00:25 Messages: 2104 Offline

Sep 20, 2018 15:51

Quote A potential client wants us to use "High profile; two consecutive B-frames" when we produce a video for them. According to Adobe, there are three options to H.264 encoding: I-Frames, P-Frames, and B-Frames. B-Frames are "bi-directional predicted frames...This makes B-frames the most efficient frame of the three." So, I suspect that they compress into smaller files than the I- and P-frames, and maybe my potential client wants the smaller size to load faster online, but it doesn't really matter why.

Question 1) Does anyone know which of these three encoding options PowerDirector (I'm on v.17) uses when it produces an H.264 MP4 video?

Question 2) And what do they mean by "high profile?" That may have nothing to do with B-frames.

I'm having a little trouble figuring out which encoding option Powerdirector uses. If anyone knows the answer to these two questions, or where I can find them, I would appreciate the help!

Thanks,
Keith

Hi,
Using PDR17[365] v. 2029 and using the default h.264 profiles for 1920x1080 and 4096x2160 @29.97fps.

The 1920x1080 file uses High@L4 profile and the 4k uses High@L5.2 profile
Both produce 2 ReFrames and both have a GOP of M=3, N=13.

M=3 usually means a GOP like this IBBP - so your 2 consecutive B frames are present?

I would suggest you do some test renders and use MediaInfo to check out your produced file parameters and then check with your client.?

Hope that helps.
Cheers
PowerDirector Moderator

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keithm57

Newbie Joined: Dec 07, 2016 09:38 Messages: 8 Offline

Sep 20, 2018 16:09

Quote

Hi,
Using PDR17[365] v. 2029 and using the default h.264 profiles for 1920x1080 and 4096x2160 @29.97fps.

The 1920x1080 file uses High@L4 profile and the 4k uses High@L5.2 profile
Both produce 2 ReFrames and both have a GOP of M=3, N=13.

M=3 usually means a GOP like this IBBP - so your 2 consecutive B frames are present?

I would suggest you do some test renders and use MediaInfo to check out your produced file parameters and then check with your client.?

Hope that helps.
Cheers
PowerDirector Moderator

Many thanks for the quick reply! We are producing 1920x1080 at 29.97fps - I guess I should have stated that.

Yes, this helps in that I can at least tell the client that our editing software meets their requirements.

I don't understand what the High@L4 profile is, or what GOP and IBBP exactly mean, but I see "high ... profile" and "2 ReFrames," which suggest that this meets the requirements.

Thanks again for the help!

Keith

the King

Senior Member Joined: Jun 30, 2010 04:10 Messages: 296 Offline

Sep 21, 2018 04:58

Quote
Question 2) And what do they mean by "high profile?" That may have nothing to do with B-frames.

Short descripsion for the profile of H.264 here, you may like to read full spec or encoder related articles/books.
https://en.wikipedia.org/wiki/H.264/MPEG-4_AVC#Profiles ------------------------------------------------------------------------------------------------
PowerDirector 365