FS5: XAVC L vs XAVC I

Amadou

Amadou

Carbonite Member
Now Sony sells us XAVC I is the high end version of XAVC L. Fine with me. However if you set the XAVC I at the same speed as the XAVC L to 100 mb/sec... by what possible magic could the XAVC I be any better? The following question is even more insane: If you set the FS5 to 150 Mb/sec (its highest internal level) and you set the FS7 to 100 Mb/sec.... could somebody tell me how in the world the XAVC I at 100 Mb/sec can outperform the XAVC L at 150 Mb/sec? This does not make any sense.
 
Its not mb/sec its mbps:
https://www.gbmb.org/mbps-to-mbs

Anyway Im not sure you have grasped the relevant internal recording options on these cameras.
You have:
FS7 4K XAVC I 10 bit 4:2:2 (intra frame) - 240mbps
FS7 4K XAVC L 8 bit 4:2:0 (long gop) - 100mbps
FS5 4K XAVC L 8 bit 4:2:0 (long gop) - 100mbps

FS7 HD XAVC I 10 bit 4:2:2- 80mpbs
FS7 HD XAVC L 10 bit 4:2:2 - 50mbps
FS5 HD XAVC L 10 bit 4:2:2 - 50mbps

In HD the XAVC L looks quite good compared to the XAVC I, although I like intra frame codecs better, the motion looks better and it just feels good to actually record independent frames.
In 4K the XAVC L is not good enough for LOG shooting since it creates banding and can't be graded properly IMO.

Common for both these cameras is that the HD footage is not as good as it could be, hence I think the 4K from the FS7 XAVC I (also utilizing the pros of downscaling, possible slight reframings and a wider aspect ratio) is the only internal recording option I would consider for a quality picture. The HD works for lots of stuff though, like shooting for the web etc.

Cheers,
Ed
 
The L stands for Long GOP.. look it up.. the I for intra.. its techie stuff .. but you,ll see why I is often preferred ..
 
Huh.... why is it prefered? :) Or to put the question differently, what visible differences are there between something filmed in Long Op and something filmed in Intra frame? Do you actually see a difference? Or is it just about simplicity in editing? Thank you.
 
Last edited:
Amadou said:
Huh.... why is it prefered? :) Or to put the question differently, what visible differences are there between something filmed in Long Op and something filmed in Intra frame? Do you actually see a difference? Or is it just about simplicity in editing? Thank you.
Click to expand...

It is really more about editing than visual differences. The long GOP codecs are more efficient as they use more frames but a lot of motion can overwhelm to some degree. Same thing for the I codecs but in reverse. Motion handling is better as each frame is encoded separately but the bit rate can get overloaded. So a high bitrate for a long GOP codec is better in the end for "normal" shooting. A very high bit rate is better for an I codec.

for editing, it is much easier for a CPU to keep track of each frame as one unit (all-I) compared to a group (long GOP - group of pictures). So the all-I codecs edit much better.
 
For some, All-I is preferred for image quality but to be honest, camera makers are usually stingy with the bitrate. So they end up being very close. If the bitrate was larger then All-I would have more advantages along with the disadvantage of more required storage.
 
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