Re: [Avid-L2] Panasonic Varicam 35 AVC-Intra Native to Avid?

I think I was conflating XAVC-S with all XAVC.  That makes sense I was just thinking staying in the same codec as the source would avoid what Netflix likes to call recompression.  Ultimately the 4096_)2160 mixdown is letterboxed into a UHD frame to make the delivery DPX files.  I've never understood why they don't want to take my original 4096_2160 for the DPX but they don't.  I guess the extra time to scale it to UHD became problematic on their end.

On Thu, Apr 30, 2020 at 05:05 PM, Mark Spano wrote:

XAVC can be either Long-GOP or Intra-frame. It is usually designated (XAVC-I or XAVC-L). There's also XAVC-S, also Long-GOP, for budget cameras.

 

Most likely Avid is giving you the choice of XAVC-I at those bit rates. Would be preposterous to have that high of a bit rate for Long-GOP, but I've been proven wrong before.

 

It is almost always the case that whoever provides Avid the codec API either gives them the ability to read/copy (consolidate) ONLY, or the ability to read/copy/write. Many AMA plugins are written just like this, often with a 'buy-to-enable-write' functionality.

 

So what does this all mean for you?

 

Consolidate if you like and you will be making nice Avid MXF media of your media. Mix down to the codec of your choice - if it is a sufficiently high bit rate intra-frame codec, you won't be losing quality, as most of those are nearly lossless at high bit rates (DNxHD, DNxHR, ProRes HQ, etc.). You can mix down to XAVC-Intra, but I feel it's only worthwhile to do so if XAVC-Intra is part of your delivery codec requirements. Otherwise, I would advise (as I almost always do) to mix down to the codec you are delivering to, and output Same As Source.

 

 

 

On Thu, Apr 30, 2020 at 4:29 PM John Moore <bigfish@pacbell.net> wrote:

Okay so it sounds like I am correct that the Panasonic Varicam 35 media is AVC-Intra, all contained in a single frame not long GOP, whereas XAVC is long GOP.  So my main question still stands.  When I go to do a video mixdown I don't see a choice to mixdown to AVC-Intra only XAVC at 320mbs or 480mbs.  I would think if Avid can consolidate the Panasonic Media with handles then it would be considered a native codec to Avid.  So why don't I see it as a choice for a video mixdown?  Am I missing something?

My curiosity is wouldn't it be cleaner to mixdown to the same codec that the source material is to avoid some sort of recompression?  The fact that I've done symphony color correction and the media is no longer just the OCN media might factor in.  Would Avid's internal workings convert the AVC-Intra to baseband or something to process the color correction element and then convert that to whatever the render/mixdown codec is?





On Thu, Apr 30, 2020 at 09:52 AM, Mark Spano wrote:

Guys, really? AVC-Intra is not Long-GOP, it's intraframe compression. AVCHD is Long-GOP, you might have been thinking of that.

On Thu, Apr 30, 2020 at 11:07 AM JBeck <jb30343@windstream.net> wrote:

Wilson, I was trying to be generous but, yes.  JB 

 

On Apr 30, 2020, at 9:34 AM, wilsonchao <wilsonchao@gmail.com> wrote:

Marcel,

 

     When JB wrote that "intra" is a "marketing term", I believe he is meant that the term is a contradiction or a falsehood, since "long GOP" necessarily means it's actually interframe, not intraframe.

 

Wilson

 

On Thu, Apr 30, 2020 at 10:00 AM Marcel B. <bncrcaxlr@gmail.com> wrote:

intraframe means that all the coding is done within the frame as oppose
to interframe where the coding is done by calculating predictions values
base on already coded other pixels.

On 30/04/2020 09:45, JBeck wrote:
> Going completely from memory so I’m likely wrong but I think AVC-Intra
> is also long GOP. The “intra” is a marketing term. JB
>
>

 

 

 

 

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