H.265 HEVC for Canon Cinema Cameras?

[Mark Dobson]

I'm just picking up news on the new Canon format, H.265 HEVC which will be included with the new XF705 camcorder.

Could this codec be added to other Canon Cameras through a firmware update? Just wondering as it would make recoding 4k on my C300mk2 a whole lot easier.

[Gary Huff]

No it can’t, encoding is done with an encoder chip, not via software.

[Cary Knoop]

Originally Posted by Mark Dobson

Could this codec be added to other Canon Cameras through a firmware update? Just wondering as it would make recoding 4k on my C300mk2 a whole lot easier.

Why do you think it would make things easier.

H.265 is harder to decode and while the compression is more sophisticated than H.264 this would only become significant for lower, destination quality, bitrates.

The higher the bitrate the less compression 'finesse' becomes a factor.

[Gary Huff]

Originally Posted by Cary Knoop

Why do you think it would make things easier.

Because 4K on the C300 Mark II is 400Mbps.

[Cary Knoop]

Originally Posted by Gary Huff

Because 4K on the C300 Mark II is 400Mbps.

I know you will disagree on this but with such a high bitrate the compression finesse of H.265 is of very little significance.

[Mark Dobson]

Thank's all for that feedback.

Yes, the 400Mbps rate was the reason for hoping for a more economical and efficient 4k codec for the C300mk2.

[Gary Huff]

Originally Posted by Cary Knoop

I know you will disagree on this but with such a high bitrate the compression finesse of H.265 is of very little significance.

Yes, because it’s wrong. 10-bit 4:2:2 H.265 on the XF-705 is 160Mbps. 160Mbps is less than 400Mbps.

[Jack Zhang]

"More efficient" often means "Throwing away more information."

Gradient issues with "blocky" gradients is MUCH WORSE with HEVC, to the point where I truly believe it should not be used in acquisition unless it has a specific profile made for it. Remember, HEVC only just drafted a "High Throughput" profile, and no hardware encoder ASICs support that yet. It's still just "Main 10." Current encoding profiles are for DISTRIBUTION, not ACQUISITION.

There's a reason Sony waited until the AVC spec had super high levels to release XAVC.

To equate the situation, to use Canon HEVC now is like using the Sanyo Xacti's H264 compression while broadcast acquisition was still 50mbps MPEG2.

There's a reason why the bitrate should be high for acquisition. Event video means you should have a dedicated person swapping cards and a LOT of storage.

[David Peterson]

Compression algorithm technology is not static, they have improved and got better over time. Not all compression methods are equal to each other.

I for one do welcome wider usage of more advanced compression tech in cameras.

[Gary Huff]

Originally Posted by Jack Zhang

"More efficient" often means "Throwing away more information."

No, it does not often mean that. "More efficient" means better algorithms (read: more CPU intensive) based on prediction, look-aheads, and how to best deal with information that doesn't read visually to the viewer in order to achieve the best result at the lowest size.

Gradient issues with "blocky" gradients is MUCH WORSE with HEVC

That is simply not true.

To equate the situation, To use Canon HEVC now is like using the Sanyo Xacti's H264 compression while broadcast acquisition was still 50mbps MPEG2.

You are equating a professional camcorder from Canon with a low-end consumer point-and-shoot from a company not known for its cameras in a professional field.

[Jack Zhang]

Originally Posted by David Peterson

Compression algorithm technology is not static, they have improved and got better over time. Not all compression methods are equal to each other.

It changes what parts of the image get less information.

In HEVC, this means low motion often doesn't even get a full set of GOP temporal frames, as it's cheating with temporal information by sometimes not doing full GOP frames if the color in motion is too similar between shades. This is extremely common in highly compressed HEVC.

With the move to H264 and HEVC, subtle gradations between stuff like a gradient of the sky become blocky the lower the bitrate. Because they limited the highest level possible for Main 10 and can only go to a certain "very specific" bitrate, You will notice these "banding" artifacts on a clear blue sky a LOT more than H264 if the bitrate isn't high enough.

[Gary Huff]

Originally Posted by Jack Zhang

In HEVC, this means low motion often doesn't even get a full set of GOP temporal frames, as it's cheating with temporal information by sometimes not doing full GOP frames if the color in motion is too similar between shades. This is extremely common in highly compressed HEVC.

"Highly compressed" being the keyword. Highly compressed anything will throw away information, that's why you give enough bitrate for HEVC to not have to do that. The difference between 10Mbps HEVC and 160Mbps HEVC.

With the move to H264 and HEVC, subtle gradations between stuff like a gradient of the sky become blocky the lower the bitrate.

Both H.264 and HEVC exhibit the same behavior with lower bitrates.

You will notice these "banding" artifacts on a clear blue sky a LOT more than H264 if the bitrate isn't high enough.

You will not notice banding artifacts more in HEVC vs H.264 at similar bitrates.

[Dan Brockett]

Originally Posted by Mark Dobson

Thank's all for that feedback.

Yes, the 400Mbps rate was the reason for hoping for a more economical and efficient 4k codec for the C300mk2.

410 Mbps is high data rate? Try shooting Cinema RAW Light with the C200. 1Gbps seems high, when we switch back to the C300 MKII, 410Mbps seems almost quaint, we end up good recording times with our 256GB CFast cards on the C300 MKII in comparison. All relative I guess but even the 1Gbps is manageable if not a little ungainly in post and data workflow.

[Jack Zhang]

I'm still waiting for a encoding ASIC that supports High Throughput HEVC before taking it seriously. That's likely 2 IBCs away, likely something like XEVC from Sony.

I'm sorry, 160Mbps if it's "Main 10" profile isn't enough.

[Gary Huff]

Originally Posted by Jack Zhang

I'm sorry, 160Mbps if it's "Main 10" profile isn't enough.

It's not "Main 10" because it's 10-bit 4:2:2 HEVC, so it's, at a minimum "Main 4:2:2 10" which isn't the same as standard "Main 10". Again, this seems to be conflating consumer side HEVC solutions with professional ones. The two aren't the same, and the codec in the XF705 will be very strong, I guarantee it.