#4 Sony XAVC

XAVC comes at #4 and #3 in my list of Tops and Flops of 2015.

You already know that XAVC has 3 variants: (bonus: wiki link for those who want a refresher)


XAVC-I is intra-frame, the highest quality variant
XAVC-L is long GOP variant
XAVC-S is consumer-oriented and will be the subject of next post: #3 Sony XAVC-S

But did you know that’s there a fourth variant and Sony is not even aware of it?

“XAVC Mark II” by Canon…

A few weeks ago, I have received a repair request for a format that Treasured could not detect.
So I parsed the damaged clip manually, and quickly convinced myself that it was a new kind of XAVC-I:
Same MXF container, same data layout, same H.264/MPEG-4 AVC video and Linear PCM audio channels.

And I also found an explanation for Treasured not detecting it as XAVC-I: H.264 encoding settings were slightly different than those I had trained Treasured for.

I thought it was just another flavor of XAVC-I, but found strange that after two years of dealing with XAVC-I, new flavors would still appear.
Nevermind, I did some tweaks to an existing XAVC-I repair kit, and I could repair the sample.

When I sent the XAVC-I preview to the customer, to my surprise he answered that preview was great, but that I got the format wrong: It was not XAVC-I, but rather Canon XF-AVC from the new C300 Mark II.

Rebuttal, the hard way.

What? I could hardly believe it, but evidence was damning:

  1. Google: Canon XF-AVC is the new 4K format in town and everybody is talking about the Canon C300 Mk II. How I had missed that remains a mystery.
  2. A quick MXFDump on the damaged file was saying it loud and clear:
  3. [ K = MXFIdentification ( 0000000000000a10 )
      [ k = CompanyName
      3c.01, l =    10 (000a) ]
           0  00 43 00 41 00 4e 00 4f 00 4e                      .C.A.N.O.N
      [ k = ProductName
      3c.02, l =    64 (0040) ]
           0  00 45 00 4f 00 53 00 20 00 43 00 33 00 30 00 30    .E.O.S. .C.3.0.0
          10  00 20 00 4d 00 61 00 72 00 6b 00 20 00 49 00 49    . .M.a.r.k. .I.I
    

    and the final nail in the coffin:

  4. X-Rays on the first 20 MB shows clear differences (left is Sony XAVC-I, right Canon XF-AVC)


X-Rays is an internal tool using space-filling curves to visualize remarkable structures inside damaged video files.

So what is actually going on?
On one side, Canon XF-AVC uses that exact same ingredients as Sony XAVC for its new 4K format, on the other side there are small implementation differences that make the two formats distinguishable if you have the right tools.

Technical false twins, if you will.

The XAVC Marketing Stunt

Canon has pulled exactly the same marketing stunt as did Sony two years ago:
Rebrand H.264/AVC as Canon XF-AVC to address 4K with a “new” format.

And there’s a good reason Canon did the same: because it worked so well for Sony with XAVC!

The advantages of coining a nice format name are manifold:

  • “New” is a magic word. Every marketer knows that.
  • Under XAVC umbrella you can encompass a variety of specs that otherwise would create confusion:
  • XAVC-S for H.264 in MP4 container
    XAVC-I for raw H.264 in MXF container, intra frame level 5.2
    and future variants can also use the XAVC branding

  • It is easier to communicate on XAVC compatibility, to certify or license XAVC third-party solutions, than to communicate on complicated H.264/AVC profiles and specifications.

The XAVC marketing trick has given a two years head start to Sony over Canon in the 4K transition.
In next post, we will explore a few interesting properties of XAVC and how Canon XF-AVC approach tends to differ.