gh5 footage recording lossless?

Do you have questions about Desktop Video, Converters, Routers and Monitoring?
  • Author
  • Message
Offline

Jan Schubert

  • Posts: 21
  • Joined: Thu Mar 19, 2015 12:04 am

gh5 footage recording lossless?

PostMon Feb 26, 2018 3:50 am

Hi.

I know it's probably not the right forum to ask. But I thought i can find someone here who might tested the GH5 in comparison to the blackmagic pocket.

I have the blackmagic pocket for quite a while now and a friend of mine is considering getting the GH5 or blackmagic.
So we both had a look at the GH5 footage we could find online.
But we still couldn`t figure out if the GH5 can record 100% lossless compressed or uncompressed.

So we had a closer look at this footage:
(http://www.4kshooters.net/2017/01/13/do ... s-footage/)

The quality looks great, but when we had a closer look we could see quite a few artefacts...(waterfall is probably a good example)
So in fact, the blackmagic pocket gave us a much nicer cleaner result.

Does anyone know if that is just because this footage is already compressed, or is it the maximum quality you can get from the GH5?

If anyone know where to get uncompressed samplefootage for the GH5, i would be really interested to see :)

Thank you very much in advance
Jan
Offline

Andrew Kolakowski

  • Posts: 4348
  • Joined: Tue Sep 11, 2012 10:20 am

Re: gh5 footage recording lossless?

PostMon Feb 26, 2018 3:46 pm

It's all compressed and far from mathematically lossless, but still decent quality.
If you want better source quality you need to use external recorder with GH5 over HDMI (record ProRes or DNxHR etc).
Offline

John Paines

  • Posts: 1710
  • Joined: Tue Jul 28, 2015 4:04 pm

Re: gh5 footage recording lossless?

PostMon Feb 26, 2018 4:12 pm

Neither camera records internally lossless or uncompressed, though the GH5 claims external is uncompressed. The BMPCC records in Prores HQ and raw, using intraframe compression. The GH5 records with either long gop interframe compression format, or intraframe like BMPCC. In my view, there is no point recording GH5 footage to an external source, given the limitations of the sensor.

Assuming the GH5 is set to use its intraframe codec, obvious differences in perceivable compression are unlikely, although you're far more likely to encounter moire with the BMPCC. But that's a different issue.
Last edited by John Paines on Mon Feb 26, 2018 4:42 pm, edited 1 time in total.
Offline

Andrew Kolakowski

  • Posts: 4348
  • Joined: Tue Sep 11, 2012 10:20 am

Re: gh5 footage recording lossless?

PostMon Feb 26, 2018 4:36 pm

This 400Mbit I frame mode is not much better if at all than long GOP modes.
I frame option needs few times higher bitrate to compensate for lack of inter frames.

If someone wants the best of out GH5 external recorder still gives advantage.
Offline

John Paines

  • Posts: 1710
  • Joined: Tue Jul 28, 2015 4:04 pm

Re: gh5 footage recording lossless?

PostMon Feb 26, 2018 4:37 pm

Show me the advantage and I'll believe it. You'll never see it, with this camera.
Offline

Andrew Kolakowski

  • Posts: 4348
  • Joined: Tue Sep 11, 2012 10:20 am

Re: gh5 footage recording lossless?

PostMon Feb 26, 2018 5:23 pm

If there is no "real world" difference then this is fine.
There will be "technical" (less compression- ProRes HQ is about 1000Mbit for UHD 30p) difference, but we know this is quite often meaningless in real world.
Offline

SkierEvans

  • Posts: 33
  • Joined: Wed Jan 24, 2018 9:59 pm
  • Real Name: Ron Evans

Re: gh5 footage recording lossless?

PostMon Feb 26, 2018 5:59 pm

John Paines wrote:Neither camera records internally lossless or uncompressed, though the GH5 claims external is uncompressed. The BMPCC records in Prores HQ and raw, using intraframe compression. The GH5 records with either long gop interframe compression format, or intraframe like BMPCC. In my view, there is no point recording GH5 footage to an external source, given the limitations of the sensor.

Assuming the GH5 is set to use its intraframe codec, obvious differences in perceivable compression are unlikely, although you're far more likely to encounter moire with the BMPCC. But that's a different issue.



Could you explain " limitations of this sensor " I have the GH5 and like it very much and am considering getting the Atomos Ninja Inferno for one main reason to record UHD 60P in 10 bit not possible internally and thereby get a better file for editing. I can then record in VlogL or HLG at this frame rate. For information I have no interest in recording slow frame rates as I like the smooth motion of 60P.
Offline

Jan Schubert

  • Posts: 21
  • Joined: Thu Mar 19, 2015 12:04 am

Re: gh5 footage recording lossless?

PostMon Feb 26, 2018 7:01 pm

Hmm interesting. That all gets quite technical to me and i might be wrong. But isn't the cinemaDNG format lossless? I mean it's compressed but just the filesize. The image quality should still keep uncompressed. So bit like a zip file, just that its unzipping when you play the clip.
That`s how i understood it at least...while recording in ProRes you will have at least a small amount of image compression.

I know that means probably looking for the details with a magnifier. And the image quality of the GH5 is great. I just try to understand, and when it comes to post-processing like keying, the image can`t be clean enough and the smallest artefacts can cause you trouble :))
Offline

Andrew Kolakowski

  • Posts: 4348
  • Joined: Tue Sep 11, 2012 10:20 am

Re: gh5 footage recording lossless?

PostMon Feb 26, 2018 7:27 pm

DNG from some BM cameras can be mathematically lossless (or not). More important is fact that BM cameras give you ability to record RAW. This is very different to already debayered/processed video.
RAW is "raw" data from the sensor (just stored as DNG files), so this is the best you can get from any camera.
Typical RAW recording is reserved for higher-end and expensive cameras.
Offline

Andrew Kolakowski

  • Posts: 4348
  • Joined: Tue Sep 11, 2012 10:20 am

Re: gh5 footage recording lossless?

PostMon Feb 26, 2018 7:31 pm

SkierEvans wrote:
John Paines wrote:Neither camera records internally lossless or uncompressed, though the GH5 claims external is uncompressed. The BMPCC records in Prores HQ and raw, using intraframe compression. The GH5 records with either long gop interframe compression format, or intraframe like BMPCC. In my view, there is no point recording GH5 footage to an external source, given the limitations of the sensor.

Assuming the GH5 is set to use its intraframe codec, obvious differences in perceivable compression are unlikely, although you're far more likely to encounter moire with the BMPCC. But that's a different issue.



Could you explain " limitations of this sensor " I have the GH5 and like it very much and am considering getting the Atomos Ninja Inferno for one main reason to record UHD 60P in 10 bit not possible internally and thereby get a better file for editing. I can then record in VlogL or HLG at this frame rate. For information I have no interest in recording slow frame rates as I like the smooth motion of 60P.


Regardless of sensor "limitations" (GH5 sensor is decent) recording format is a 2nd and separate matter. You always want it as low compressed as possible or the best RAW. Definitely it's not fully pointless to record externally as there are modes which are not even 10bit internally (regardless how heavily they are compressed).
Ideally I would like to have RAW from GH5 to external recorder.
If you know that ProRes recording gives not enough advantage over internal recording then fair enough.
Offline
User avatar

Scott Smith

  • Posts: 953
  • Joined: Sat Apr 13, 2013 12:51 pm

Re: gh5 footage recording lossless?

PostTue Feb 27, 2018 6:53 pm

We have several GH5 cameras. Much of the time, the compressed format is great to work with. Sometimes, when the project is more critical or we want the 10-bit sampling for a chroma key, we use external recorders, in ProRes444. The Hyperdeck or video assist would probably do this fine. But we use Atomos Shogun Inferno with our GH5s. They play very well together.
Last edited by Scott Smith on Tue Feb 27, 2018 9:48 pm, edited 1 time in total.
Scott R Smith
BMD Stuff I use: ATEM 2-M/E, 4 x ATEM PS 4K, Broadcast Videohub, 6 Hyperdeck Pros, 4 Hyperdeck Shuttles, Multidock, Smartscope Duo, Smartview, Intensity Extreme, Decklink Studio, and lots of Miniconverters and Open Gear Converters.
Offline

Dan Sherman

  • Posts: 475
  • Joined: Fri Jul 01, 2016 11:07 pm

Re: gh5 footage recording lossless?

PostTue Feb 27, 2018 8:16 pm

Scott Smith wrote: Sometimes, when the project is more critical or we want the 10-bit sampling for a chroma key, we use external recorders, in ProRes444.


why ProRes 444? The GH5 HDMI out is only 10 bit 4:2:2 maximum!
Offline

Andrew Kolakowski

  • Posts: 4348
  • Joined: Tue Sep 11, 2012 10:20 am

Re: gh5 footage recording lossless?

PostTue Feb 27, 2018 8:47 pm

Yep, you just wasting space. 444 is also same compression ratio as HQ, so there is 0 gain. ProRes XQ would make some sense for even lower compression ratio, but 444 is useless in this case.
Offline
User avatar

Scott Smith

  • Posts: 953
  • Joined: Sat Apr 13, 2013 12:51 pm

Re: gh5 footage recording lossless?

PostTue Feb 27, 2018 9:08 pm

My bad. You are correct, and we do record in ProRes422.
Scott R Smith
BMD Stuff I use: ATEM 2-M/E, 4 x ATEM PS 4K, Broadcast Videohub, 6 Hyperdeck Pros, 4 Hyperdeck Shuttles, Multidock, Smartscope Duo, Smartview, Intensity Extreme, Decklink Studio, and lots of Miniconverters and Open Gear Converters.

Return to Post Production

Who is online

Users browsing this forum: No registered users and 7 guests