Hi,
We have a new Sony Fs7 and I'm noticing some pixelation and banding, especially on flat colour. The camera is shooting in XAVC Intra.
You have to AMA link to the file structure that the camera produces, so first try was AMA link>transcode to DNXHD120.
After noticing the banding, I tried DNXHD185x, which produces better results, but we haven't got the space to always use 185x.
After that I tried transcoding to Sony's XAVC100 Intra codec, which is smaller in terms of file size and produces results similar to 185x, as far as I can see.
But with all of these, there is still quite pronounced banding on some shots, especially when you try and grade (even a little).
Has anyone experienced this, and does anyone have a solution?
Many thanks
I believe (but may be wrong) that your camera source is a 10bit file. So going to any 8bit codec will really increase chances for the banding you see.
Plus, is the original codec any of the LOG codecs the Fs7 is capable of? If so you REALLY need to stay in a 10bit codec to not screw up the intentions of a LOG encoding.
Jef
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Jef Huey
Senior Editor
Hi Jef, thanks for replying.
It is a 10 bit source, yes, and a LOG codec. Catalyst browser reports codec as 'AVC Intra CBG Class 100' - I'd have to check with the cam op for any further info.
Although the banding is lessened by using DNXHD185x or the XAVC Intra codec to transcode to, it's still quite pronounced. For comparison, we have a Blackmagic Cinema camera often used on the same shoots. This records in either Prores (usually proresHQ) or DNXHD185x, so both 10 bit, and we usually shoot in 'film' mode (i.e. BM version of S-log) but I don't get any of the same pixelation/banding when transcoding to DNXHD120 for edit. It just seems the Sony footage isn't looking as good as the Blackmagic, and I kind of expected that it should look better as it cost 5 times as much!
Are you transcoding and burning in the LUT or leaving it live?
And silly question - are you viewing the result with the sequence quality setting in 10bit?
Hi Jef
jef:Are you transcoding and burning in the LUT or leaving it live?
Actaully, I'm not sure. We got the camera for a bunch of shoots with tight turnaround so I haven't had much chance to reserarch anything. I noticed Avid seems to AMA link with a LUT applied automatically - I thought this might be the problem so I removed it in source settings so it brings it in as 'flat' colour - can't see any banding then but as soon as you grade it at all (using Avid CC, curves etc) the banding returns.
jef:are you viewing the result with the sequence quality setting in 10bit?
Good point - I believe so but I'll recheck!
Cheers
I dont transcode my footage - I just consolidate. Avid handles the AVC 10bit codec natively. Try that - avoding the pain of transcoding. Just did a 4k shoot yesterday against infinite white with lost of natural vignettes/grads/falloffs. No contouring.
The only downside to consolidate is that Sorenson wont handle the XAVC codec andf thus quick time ref exports, so I have lost my supewr fast QT Ref workflow and have to painfully mixdown. Whats worse is that it was also a 'tough luck' approach from Sorenson. Its just AVC 100 H264 after all...
Ultimate 2022.12.1, Blackmagic Intensity Pro, WIN 11 on 7000Mbps M.2 SSD, Nvidia Quadro P4000, Asus Pro Art Z690 i9 12900k 5.0 GHz, 8TB M.2 SSD - its nippy!
Thanks for the tips guys,
I think the Fs7 footage does have a problem transcoding to DNXHD, even 185x. The problem I had was a combination of that and also (doh) I was not viewing in 10bit. Transcoding to XAVC and adjusting the view to 10bit seems to have cured it.
DIESELE:I dont transcode my footage - I just consolidate. Avid handles the AVC 10bit codec natively.
Thanks, I haven't had time to try this yet. We operate from a SAN via 1gig ethernet so usually it's faster to transcode to DNX - Avid seems to be faster this way, but I'll try this method too.
One question though:
DIESELE:I have lost my supewr fast QT Ref workflow and have to painfully mixdown.
What do you mixdown to? XAVC or DNX (or something else)? Just asking as we have another problem since introducing Fs7 into the workflow. We now get sections of exports (Same as Source) with just a white screen. There doesn't seem to be any consistency as to when this happens - one timeline will have these white sections and another from the same shoot won't - it's also not always on the fs7 footage, weirdly, sometimes it's on blackmagic transcoded to DNX (our usual workflow). So I'm also having to mixdown now to avoid this...
Consolidate is just a re-wrap - has to be quicker!
I get white screen in Sorenson if its native XAVC media. So I set render settings to be DNX - so when you add an effect it transcodes. This is fine if you are grading every shot. If not you will have to endure the pain of the mixdown.
Hi, I'm sure it will be - just have a few deadlines today so I don't have time to reimport etc, but I'll try it on the next one.
DIESELE:So I set render settings to be DNX
Yeah, render settings are on DNX (I think) and it's all graded. Sometimes the white screen happens on a rendered effect (i.e. a transition) and sometimes just on a whole section of video, until the next cut. Weird. I suppose I could try render settings on XAVC and see if that makes a difference. Right now though, for speed, I've just mixed down the whole timeline to DNX.
New projects default to same as source render. Force it tio DNX :)
Hi, first chance I've had to log back on for a few days - just to say thanks for the tips, and workflow from Diesele. I'm now consolidating rather than transcoding and it works well.
Still get more pixelation/banding than I was expecting, I must admit. It just doesn't seem as good quality as the blackmagic cinema camera footage, particularly when grading, but I guess the fs7 is recording in 100mbps (ish) rather than 185 on the BMCC so maybe it's just that.
Anyway cheers again!
Banding/contouring is down to bits at the encoding stage not bitrate. FS7 does 10 bit natively - this is 1024 levels from black to white. Std 8 bit is 255 levels - you will see banding on grads... But on the FS7?! Must be your o/p card or screen or settings? Are you using a $$$ 10 bit screen?!
Dan,We've found occasionally our FS7 won't trasncode. Something to do with the data track we've found.Our workaround in AMA as normal, then unlink the clips, modify the tracks to remove the data track and audio ones you dont want like 5-8 then relink. Transcode works perfectly after that.DiesleAn option away from QT ref is AMA file eport. Not as quick as QT ref, but not far behind, no need to mixdown. It can create an MXF 01pa MXF using your choice of DNx like 185X, One odd bug off it though, is you must have an even number of audio tracks, which sometimes might mean adding a blank track in avid!!
AntCaladine: We've found occasionally our FS7 won't trasncode. Something to do with the data track we've found.Our workaround in AMA as normal, then unlink the clips, modify the tracks to remove the data track and audio ones you dont want like 5-8 then relink. Transcode works perfectly after that.
We've found occasionally our FS7 won't trasncode. Something to do with the data track we've found.Our workaround in AMA as normal, then unlink the clips, modify the tracks to remove the data track and audio ones you dont want like 5-8 then relink. Transcode works perfectly after that.
An other way to get rid of a corrupt(?) data track is to create a subclip without it: Load the clip in the source monitor. Press Mark Clip. Deselect the data track on the source side on the timeline (and audio tracks that are not needed) and create a subclip.
Then the subclip can be transcoded. This might work better in an Isis/Interplay environment where unlink and modify could create problems (or at least some very sinister looking dialog boxes :-)).
Kåre Nejmann
Danish Broadcasting Corporation - DRAarhus, Denmark
Thanks guys. In passing, is there any way to avoid ingesting 5 mute audio tracks when consolidating - 3 is all I need. Silent tracks take up much MXF folder space and probably processing power!
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