H.265 only being recorded at 60 mbps?

smiller · Jan 30, 2017

When looking at a couple of P4P video files in Windows Explorer (Properties - Details) the reported bitrate of 4K/30 fps H.264 files is around 100 mbps as expected, but H.265 files (whether MP4 or MOV) only show 60 mbps (and it's not a Windows bug because VLC player reports the same.) The DJI specs indicate that 4K/30 fps should be 100 mbps in either format. Am I missing something?

qtonic · Jan 31, 2017

4K @ 30fps should be 100Mbit/s for both h.264 and h.265. I've tested it myself to verify.

I'm not sure what's going on with yours. 720 @ 120fps is the only h.265 setting that should record at 60Mbit/s.

gr8pics · Jan 31, 2017

smiller said:
When looking at a couple of P4P video files in Windows Explorer (Properties - Details) the reported bitrate of 4K/30 fps H.264 files is around 100 mbps as expected, but H.265 files (whether MP4 or MOV) only show 60 mbps (and it's not a Windows bug because VLC player reports the same.) The DJI specs indicate that 4K/30 fps should be 100 mbps in either format. Am I missing something?

Its indicated max bitrate, camera uses variable bitrates when recording.
In short, variable bitrates encoding is that it allocates a higher bitrate to the more complex segments of media files and lower bitrates to the simple segments.
So, the complexity of the scene is what determines the bitrate...

qtonic · Jan 31, 2017

gr8pics said:
Its indicated max bitrate, camera uses variable bitrates when recording.
In short, variable bitrates encoding is that it allocates a higher bitrate to the more complex segments of media files and lower bitrates to the simple segments.
So, the complexity of the scene is what determines the bitrate...

Even with a relatively static scene I only see the current bit rate jump around a little when viewing the (nearly) realtime report in VLC. I do not think it would ever go to 60Mbit/s

gr8pics · Jan 31, 2017

Try a scene with fast panning, moving objects etc, tilt up in the sky, tilt down at the ground, and see how bitrate behaves then...

smiller · Jan 31, 2017

Yes, it was a static scene and it occurred to me that motion might have an effect, yet with the same static scene H.264 shows a full 100 mbps so the lack of motion is not affecting max bitrate (at least not for H.264.)

$gambino$ · Jan 31, 2017

If u go to dji specs show that it can only record at 100 in h.264 the 60 is h.265

smiller · Jan 31, 2017

$gambino$ said:
If u go to dji specs show that it can only record at 100 in h.264 the 60 is h.265

No, at 4K/30 fps the specs say 100 mbps for both codecs.

smiller · Jan 31, 2017

I just tested again but this time with a lot of movement and on that attempt H.265 showed 100 mbps as it should, so mystery solved. Interesting that H.265 bitrate changes based on image content but H.264 does not.

Deleted member 27337 · Jan 31, 2017

Forgive me for asking, but what is the major difference between h.264 vs h.265? Is one better than the other?

$gambino$ · Jan 31, 2017

Smiller which program do u use for h.265 work?

smiller · Jan 31, 2017

tonyt76 said:
Forgive me for asking, but what is the major difference between h.264 vs h.265? Is one better than the other?

H.265 uses a more complex coding algorithm that is more efficient, so an H.265 stream is capable of handling more information (image detail) than an H.264 stream in the same bandwidth. The result is that in theory and sometimes in reality an H.265 file at 100 mbps can result in a higher image quality than H.264 at the same speed, but the actual difference will be dependent on a number of factors.

The downside to H.265 is that encoding/decoding is more processor-intensive than H.264 (meaning slower PCs might struggle with it), and it is also not yet as universally supported as H.264. Windows 10 can play H.265 files (assuming your PC is fast enough) as can most of the higher-end editing programs (I happen to use Adobe Premier Pro, but that is probably overkill for most uses.) Lower-end editing packages might not yet support H.265 although that is changing.

You can also transcode H.265 to an intermediate file format for editing purposes but that's a whole other topic.

ianwood · Jan 31, 2017

Simply put, the primary difference is H.265 requires more processor power and less storage throughput to get the same quality as H.264.

If H.265 records at up to 100mbps and H.264 does as well, the H.265 recording could, in theory, contain more image data than H.264.

Tomas Wangen · Jan 31, 2017

qtonic said:
Even with a relatively static scene I only see the current bit rate jump around a little when viewing the (nearly) realtime report in VLC. I do not think it would ever go to 60Mbit/s

I was quite surprised when I had a look at some of my clips now and found that it does certainly go down to 60 for very static content. Most clips end up around 97-100. (h265/30/4k)

Roamer105 · Jan 31, 2017

gr8pics said:
Its indicated max bitrate, camera uses variable bitrates when recording.
In short, variable bitrates encoding is that it allocates a higher bitrate to the more complex segments of media files and lower bitrates to the simple segments.
So, the complexity of the scene is what determines the bitrate...

If the file attributes say 60Mb/s then that is what it is. Variable bit rate has nothing to do with that. The attributes will be set to max bitrate. Furthermore I doubt very much that the DJI encoder is working at variable bitrate.

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