x264 for archiving ?

[audyovydeo]

Hello

I still haven't made up my mind whether I archive x264-encoded footage. I need people's input on this.
As far as I can tell, there are three ways to see it :


using lossless (QP or CRF=0)
using keyframe-only (-I 1 -i 1)
using intra-only compression (is this same as above ???)


the problem I found with x264 lossless is that it produces bitrates higher than the original camcorder DV footage >> what's the point !

I occasionally encode using keyframes only, but only for sports footage that I want to play back in very slow motion, or frame-by-frame.

Also, if used for archiving, one would be dependant on neuron2's DGAVCindex to decode to raw, edit, etcetera.
So all in all I'm still unconvinced, would love the community's experience on this

cheers
audyovydeo

[Dark Shikari]

using intra-only compression (is this same as above ???)Yes it is the same.
the problem I found with x264 lossless is that it produces bitrates higher than the original camcorder DV footage >> what's the point !Of course, lossless compression is always larger than lossy.

Also, if used for archiving, one would be dependant on neuron2's DGAVCindex to decode to raw, edit, etcetera.
So all in all I'm still unconvinced, would love the community's experience on thisOnly if your video editing system is ancient and doesn't support formats released this century.

I generally use FFVHUFF for an editing format personally.

[audyovydeo]

Hello DS thanks for answering


Of course, lossless compression is always larger than lossy.


DV is lossless last time I checked !?


Only if your video editing system is ancient and doesn't support formats released this century.


I guess that automatically disqualifies my Premiere v5.1c ;-)

I generally use FFVHUFF for an editing format personally.

me too. But what's your archiving format ?

So apart from upgrading Premiere by - what ? - half a dozen versions, what settings should be used for archival x264 ?


cheers
a/v

[Inventive Software]

DV is NOT lossless. It's a CBR digital tape format. http://en.wikipedia.org/wiki/DV

[audyovydeo]

DV is NOT lossless. It's a CBR digital tape format. http://en.wikipedia.org/wiki/DV

I stand corrected.

so, if I read the H.264 wikipedia :


In addition, the standard contains four additional all-Intra profiles, which are defined as simple subsets of other corresponding profiles. These are mostly for professional (e.g., camera and editing system) applications:

* High 10 Intra Profile: The High 10 Profile constrained to all-Intra use.
* High 4:2:2 Intra Profile: The High 4:2:2 Profile constrained to all-Intra use.
* High 4:4:4 Intra Profile: The High 4:4:4 Profile constrained to all-Intra use.
* CAVLC 4:4:4 Intra Profile: The High 4:4:4 Profile constrained to all-Intra use and to CAVLC entropy coding (i.e., not supporting CABAC).


which were introduced with the April 2007 amendment to the standard, my High-(10)-Intra command-line should be :

-A i4x4,i8x8 -8 --subme 5 -t 1 --no-dct-decimate --no-fast-pskip -I 1 -i 1 --direct spatial


except that it gives me :

x264 [info]: mb I I16..4: 22.7% 54.4% 22.9%
x264 [info]: 8x8 transform intra:54.4% inter:-1.$%




huh ?
a/v

[Dark Shikari]

-A i4x4,i8x8 -8 --subme 5 -t 1 --no-dct-decimate --no-fast-pskip -I 1 -i 1 --direct spatialHalf of those settings don't even apply to intra macroblocks... all you need is --8x8dct --keyint 1 --trellis 1 --subme 5 (I'd use a higher subme personally).

x264 [info]: mb I I16..4: 22.7% 54.4% 22.9%
x264 [info]: 8x8 transform intra:54.4% inter:-1.$%
That's normal...

[audyovydeo]

Half of those settings don't even apply to intra macroblocks... all you need is --8x8dct --keyint 1 --trellis 1 --subme 5 (I'd use a higher subme personally).


DS,
you're right I'm just used to adding/removing no-dct & no-fast-pskip in block whenever I set/remove trellis -- didn't think of them in this context.

is "-A i4x4,i8x8" OK or do you mean "-A none -8" ??


a/v

[Dark Shikari]

DS,
you're right I'm just used to adding/removing no-dct & no-fast-pskip in block whenever I set/remove trellis -- didn't think of them in this context.

is "-A i4x4,i8x8" OK or do you mean "-A none -8" ??


a/vJust leave analyse on the default, no need to change it.

I also don't understand what no-dct-decimate has to do with trellis, except for the fact that 8x8 trellis serves as inherently optimal decimation, and is therefore used in place of dct-decimate for 8x8dct blocks.

[audyovydeo]

I also don't understand what no-dct-decimate has to do with trellis, except for the fact that 8x8 trellis serves as inherently optimal decimation, and is therefore used in place of dct-decimate for 8x8dct blocks.

it's an option I have't yet come to grips with.
I'd just gathered from various postings that it's use was suggested in conjunction with trellis, so i dumbly did.

Funny, I just realised that these three cmdlines :

set intra=-A none -8 --subme 5 -t 1 -I 1 --direct spatial
set intra=-A i4x4,i8x8 -8 --subme 5 -t 1 -I 1 --direct spatial
set intra=-8 --subme 5 -t 1 -I 1 --direct spatial

give exactly the same result, as if -A option is ignored.
I realised I still have a lot to learn concerning x264 usage :( :( :( ... back to the drawing board ...


Thanks for your assistance, DS (and InventiveSW)

cheers
a/v

[Dark Shikari]

give exactly the same result, as if -A option is ignored.Yes, because --analyse controls analysis in inter frames only. Intra frames use all available partitions no matter what.