FS7: H.264 videobit rate for editing

Ben Scott said:
Yes you've said that before but not explained why you are transcoding to that to edit over and above cutting with the original rushes or just offlining via proxies. What is it you're gaining by having this stage of transcoding?
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You would not need to transcode as XAVC Intra is already H.264-intra.

I am merely responding to generalizations that claim that H.264 is somehow inferior to ProRes or DNxHD.
 
bengiles said:
Erm... Sony?

Choose from the FS7, F5, F55 etc.

All use XAVC Intra codec.

... which is an H264 codec, no?
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Doh!... I guess it technically is.... Sony just came up with their own version of it - which I suppose all the mfg's have at this juncture. My bad... this confusing thread still has me scratching my head.
 
markfpv said:
Doh!... I guess it technically is.... Sony just came up with their own version of it - which I suppose all the mfg's have at this juncture. My bad... this confusing thread still has me scratching my head.
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I know what you mean.

I just couldn't help being a smart arse. :-)
 
NLE's decode long GOP interframe codecs a full GOP at a time, not frame by frame. Those decoded frames have to be buffered as uncompressed frames in ram. The higher the compression, the longer the GOP, the more processing overhead to decode it. High quality short GOP codecs in the 5-15 frame range are fine with two video streams for editing on average quad core machines. Anything longer than a 30 frame GOP can get problematic without serious multi-core CPU power and at least 16GB ram.
If you have the disk space to store and edit your XAVC-i originals without performance issues there is no reason to convert to anything else, especially not anything more compressed.
 
Slightly off topic but along the same lines... What is general opinion of transcoding XAVC-I to ProRes422 vs ProRes422(HQ)? I'm referring to edit/post NOT in acquisition via external recorder.

Please check my math but it looks like the FS7 produces 4K 23.98 XAVC-I @ 960mbps which equates to 120MB/s and the ProRes422 spec states it's 126MB/s and from what I understand all ProRes flavors are 10bit; maybe not (LT) but at least ProRes422 and upward. So is there any benefit to transcoding to ProRes422(HQ) at all? It has a more bandwidth @ 189MB/s but the FS7 cannot take full advantage of it.

Just curious on what the consensus is...
 
digitalinnovations said:
Slightly off topic but along the same lines... What is general opinion of transcoding XAVC-I to ProRes422 vs ProRes422(HQ)? I'm referring to edit/post NOT in acquisition via external recorder.

Please check my math but it looks like the FS7 produces 4K 23.98 XAVC-I @ 960mbps which equates to 120MB/s and the ProRes422 spec states it's 126MB/s and from what I understand all ProRes flavors are 10bit; maybe not (LT) but at least ProRes422 and upward. So is there any benefit to transcoding to ProRes422(HQ) at all? It has a more bandwidth @ 189MB/s but the FS7 cannot take full advantage of it.

Just curious on what the consensus is...
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Your maths are always going to be wrong if you don't know the difference between Mbps and mbps.

The FS7 uses 240 Mbps at 4k 24fps.

There's no point transcoding unless your NLE can't handle XAVC very well.

What do you mean by this, 'It has a more bandwidth @ 189MB/s but the FS7 cannot take full advantage of it.' ??
 
Well that's why I come here... for big-brained individuals like yourself :)

I should probably clarify a bit: Most of my projects I will shoot in 4K but my deliverable is 1080 so everything is down-rez'ed, which I think is fairly common-place right now and I'm trying to decipher if there are any benefits to using ProRes422(HQ) instead of the standard ProRes422. My Google search for data rates on the ProRes formats also lead me astray; it looks like ProRes422 1080 @ 23.98 is 147Mbps and ProRes422(HQ) is 220Mbps. SO given that information is there a benefit to exporting to ProRes422(HQ) instead of ProRes422?

Also, I shouldn't have used the term "transcode" above either; I tend to edit the XAVC but when I export my edited pieces (whether that be the final product or an edit to take into AE for graphics, etc.) I have to make a choice on what that "Texas Master" format will be. Obviously, that won't be XAVC-I ... Although someone will probably chime in that it is for them because... well... snark. This is the internet after all ;)
 
digitalinnovations said:
Well that's why I come here... for big-brained individuals like yourself :)

I should probably clarify a bit: Most of my projects I will shoot in 4K but my deliverable is 1080 so everything is down-rez'ed, which I think is fairly common-place right now and I'm trying to decipher if there are any benefits to using ProRes422(HQ) instead of the standard ProRes422. My Google search for data rates on the ProRes formats also lead me astray; it looks like ProRes422 1080 @ 23.98 is 147Mbps and ProRes422(HQ) is 220Mbps. SO given that information is there a benefit to exporting to ProRes422(HQ) instead of ProRes422?

Also, I shouldn't have used the term "transcode" above either; I tend to edit the XAVC but when I export my edited pieces (whether that be the final product or an edit to take into AE for graphics, etc.) I have to make a choice on what that "Texas Master" format will be. Obviously, that won't be XAVC-I ... Although someone will probably chime in that it is for them because... well... snark. This is the internet after all ;)
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You only become a big brained individual by working this sort of thing out for yourself.

Surely you can export the different versions of ProRes and then eyeball the files to see whether it is worth the extra data rate? You might find you need to master in ProRes4444 but you can only make that determination by actually testing for yourself as your results will be influenced by the content you are mastering, things like high frequency detail and gradients need more data than static solid blocks of colour.
 
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