P4P bitrate question

[LVarys]

Hi all,

I have a question about the P4Ps bitrate. This is what DJI's website says:

More powerfulvideo processing supports H.264 4K videos at 60fps or H.265 4K at 30fps, both with a 100Mbps bitrate

My understanding is that with h265 you get a better quality than h265 with the same bitrate.

So to get the best quality you choose h265 and 30fps correct ? Because with h264 you can store less details in 100mbps. And you have 30 frames in stead of 60 so less data per second.

Or isn't this correct ?

 

[Dome]

The argument is techically quite complex, but I simplify in this way:
1. H265 (HEVC) permit 40-50% less bitrate, compared to the same quality of H264.
2. Both codec can process same resolutions, but obvously H264 need roughly double the bitrate of H265 to render same quality on a storage.
3. Both codec are subject to complex algorithms to make the compression. The H265 algorithms require 30-40% more processor capability than H264.
4. The output quality of both depends by the quality of the implemented compression algorithms, that I repeat, depend on about 100-120 different internal parameters (we users have no knowledge about DJI algorithms they implemented)
5. H264 provides resolutions to 4K@60fps, where H265 go to 8k@300fps.

The base concept are similar between H264 and H265, but different implementation of frame index and prediction. Please read this interesting article: #4 Concept Series : What is the difference between HEVC (H.265) and H.264 (MPEG-4 AVC)

So to get the best quality you choose h265 and 30fps correct ? Because with h264 you can store less details in 100mbps. And you have 30 frames in stead of 60 so less data per second.

Yes theorically it is right, but I'm afraid that DJI has not yet a good H265 encoder on P4Pro camera...

 

[F3honda4me]

So if you are recording in h265, when you render final videos after post do you also need to render them in h265 to maintain the benefit? Or is a final render to h264 still beneficial even if the original footage was h265?

 

[LVarys]

The argument is techically quite complex, but I simplify in this way:
1. H265 (HEVC) permit 40-50% less bitrate, compared to the same quality of H264.
2. Both codec can process same resolutions, but obvously H264 need roughly double the bitrate of H265 to render same quality on a storage.
3. Both codec are subject to complex algorithms to make the compression. The H265 algorithms require 30-40% more processor capability than H264.
4. The output quality of both depends by the quality of the implemented compression algorithms, that I repeat, depend on about 100-120 different internal parameters (we users have no knowledge about DJI algorithms they implemented)
5. H264 provides resolutions to 4K@60fps, where H265 go to 8k@300fps.

The base concept are similar between H264 and H265, but different implementation of frame index and prediction. Please read this interesting article: #4 Concept Series : What is the difference between HEVC (H.265) and H.264 (MPEG-4 AVC)



Yes theorically it is right, but I'm afraid that DJI has not yet a good H265 encoder on P4Pro camera...

Thanks ! Oke so in theory i'm correct the H265 4K 30fps should contain more details than H264 4K 30fps. But build in encoder quality may affect that.

 

[Dome]

So if you are recording in h265, when you render final videos after post do you also need to render them in h265 to maintain the benefit? Or is a final render to h264 still beneficial even if the original footage was h265?

H265 has some benefit mostly becouse, for example, a video file of 1GB is comparable in quality to a 1,8GB H264 file (using same output parameters). At the moment an H265 decoder with good quality is supported by small number of video appliance (TV, Media player etc..), so only professional services or video maker does benefit from it. If you are going to show movie to family and friends better to stay with a final render in H264... Remember that H265 encoder needs double the time of a double pass H264 to render output

 

[That Cicero Guy]

Is there any way to adjust the bitrate manually on the P4P or on any DJI drone in general? 80mb/s is a little extreme for H264 video. I've done everything on my music videos with a max of 30 to 40 and see hardly any artifacts. Right now, it looks like it's doing VBR on my P4P at an extremely high rate.