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View Full Version : TCXD450 "compatible" mpg files are out of spec for encoding profile used



spotduster
05-16-2012, 06:58 PM
The "compatible" mpg files being produced by the TCXD450 are out of official H.262/MPEG2 specification. They are encoded at 100 Mbit/s using a profile flag of main (and a level of high). According to specs (http://en.wikipedia.org/wiki/H.262/MPEG-2_Part_2) the main profile is only compatible up to 80 Mbit/s.

This failure to meet specs is causing us serious problems with smart rendering in Sony Vegas. All our files are having to be completely rendered twice before they reach final product status. We find this totally unacceptable.

There are two possible solutions:
1. Change the encoding profile flag from main to high to meet proper MPEG specs (http://en.wikipedia.org/wiki/H.262/MPEG-2_Part_2), or
2. Lower the "compatible" bit rate to 80 Mbit/s to match the official main profile to fully meet MPEG specs.

Interestingly enough the "high" recording setting on the TCXD450 does produce a proper spec MPEG2 file (it will smart render fine in Sony Vegas) but sadly we cannot use it because TMPGEnc 5 (our final down render step) won't accept 4:2:2 files yet. We use TMPGEnc 5 because of it's powerful batch capabilities to produce every final format we need in one batch.

We filed a bug report, but also posting here for any useful input.
(https://fogbugz.newtek.com/default.asp?46662_omu36a3t)

SBowie
05-16-2012, 09:01 PM
Interesting, I'll look into it, thanks.

SBowie
05-17-2012, 10:39 AM
So, as you know, there's an open case investigating this now, and those involved are looking for additional details. Just as a tangential discussion, I'm wondering whether you have tried an AVI based workflow instead, given that you're running Windows-based apps?

spotduster
05-17-2012, 11:03 AM
Avi was our workflow in VT5 and we smart-rendered everything. (We were using the main concept DV25 codec.)

The "high" recording profile on the TCXD will smart-render with a proper matching profile in Vegas, but we can't use it because TMPGEnc 5 (our final batch down-render solution) won't accept 4:2:2 video.

This is not a problem with Vegas at all. It's doing what it's supposed to and observing proper specs. The "compatible" recording on the TCXD is out of spec and Vegas refuses to smart-render it as a result. Vegas won't even let you enter 100 Mbit/s on a [email protected] profile, if you try to it changes it to 80, and then of course it won't smart-render now because of the bit-rate mismatch.

SBowie
05-17-2012, 11:30 AM
Avi was our workflow in VT5 and we smart-rendered everything.[/U]But you're not using it now - howcome?

spotduster
05-17-2012, 11:31 AM
You can't enter bit rate's outside of MPEG-2 spec in Vegas, therefore it disables smart rendering because the "compatible" TCXD files are not in spec because they are 100 Mbit/s with a main profile flag. If the profile flag in the recordings was just changed to "[email protected]" it would instantly solve the problem.

Anyone with Vegas can check this by setting up the template below. (Make sure to exactly match your video, we happen to be using 1080p.) Also disregard my notes in the profile photos, they are from another profile we use and don't apply here.
http://www.sealingtime.com/technical-resources/testing/TCXD450/render-settings-1.jpg
http://www.sealingtime.com/technical-resources/testing/TCXD450/render-settings-2.jpg
http://www.sealingtime.com/technical-resources/testing/TCXD450/render-settings-3.jpg
http://www.sealingtime.com/technical-resources/testing/TCXD450/render-settings-4.jpg
http://www.sealingtime.com/technical-resources/testing/TCXD450/render-settings-5.jpg

We can smart render video recorded in the "high" setting, and Vegas will
do it, because it's correct MPEG-2 spec ([email protected] can go to 300
Mbit/s), but it's not compatible with the rest of our work flow (TMPGEnc
5). Since you have Vegas there (Andrew) you can reproduce this easily.

1. Create test clip on TCXD in "compatible" profile.
2. Throw clip in Vegas. (We've tried versions 9-11.)
3. Create profile that matches the video exactly (to enable smart
rendering.) (See attached images.)
4. You will discover quickly that you can't enter 100 Mbit/s. (Like I
say, I know a way to force it, and that results in the also attached
error.) If you enter 80 then you aren't smart-rendering.

spotduster
05-17-2012, 11:33 AM
But you're not using it now - howcome?

The TCXD450 won't record to AVI. MPEG would work fine and we'd have a loss-less workflow if not for this one problem.

SBowie
05-17-2012, 11:46 AM
The TCXD450 won't record to AVI.Aah, right, I'd forgotten that. 450 EXTREME and 455 both do, which is why it slipped my mind. If you had either of the latter, does your problem go away?

spotduster
05-17-2012, 11:55 AM
Aah, right, I'd forgotten that. 450 EXTREME and 455 both do, which is why it slipped my mind. If you had either of the latter, does your problem go away?

That would be theoretical because we don't have the codecs to test with. However, Vegas will often smart-render from VFW based codecs to (matching) VFW based codecs, IF you have every setting perfect, it's a good day, and it feels like it. ;)

With MPEG-2 all Vegas seems to care about to smart-render that I see so far is:

format must match
codecs must match
bit-rates must match (this is where we are having the problem, one of these 2 probs needs fixing)
I vs P must match
profile and level must match (this is where we are having the problem, one of these 2 probs needs fixing)
resolution must match
I, B & P frame setup must match

Seems if you get those to match it will smart-render. Trust me when I say we've done a LOT of testing.

spotduster
05-17-2012, 12:06 PM
Aah, right, I'd forgotten that. 450 EXTREME and 455 both do, which is why it slipped my mind. If you had either of the latter, does your problem go away?

What's the diff between 450 and 455?

SBowie
05-17-2012, 12:07 PM
That would be theoretical because we don't have the codecs to test with. However, Vegas will often smart-render from VFW based codecs to (matching) VFW based codecs, IF you have every setting perfect, it's a good day, and it feels like it. ;)Yes, I've been reading up and it does seem rather fussy. (Actually, to be correct, I guess I'd have to say that it's the MC setup that's being persnickety, not Vegas per se).

While Engineering is mulling over possible changes, would you be interested in testing a small AVI file to see if it does pass the gauntlet?

SBowie
05-17-2012, 12:11 PM
What's the diff between 450 and 455?If you were to think that 455 is the next advancement on a 450 EXTREME, you wouldn't be too far off the mark. In the current context, 455's IsoCorder tech captures to a truly cross-platform friendly Quicktime format by default. It also supports capture to the two current MPEG-2 formats, plus AVI, and with some limitations, H.264 (.mp4).

spotduster
05-17-2012, 12:12 PM
While Engineering is mulling over possible changes, would you be interested in testing a small AVI file to see if it does pass the gauntlet?

Yes, very interested, but won't we need the codec it was recorded with? Also it will need to be long enough that smart-render engages which can sometime take several seconds.

SBowie
05-17-2012, 12:15 PM
Yes, very interested, but won't we need the codec it was recorded with?The latest codecs are on the website, in your personal downloads section. I'll prepare a test AVI file and email you a download link.

spotduster
05-17-2012, 12:20 PM
If you were to think that 455 is the next advancement on a 450 EXTREME, you wouldn't be too far off the mark. In the current context, 455's IsoCorder tech captures to a truly cross-platform friendly Quicktime format by default. It also supports capture to the two current MPEG-2 formats, plus AVI, and with some limitations, H.264 (.mp4).

What is the upgrade cost from a 450 to 455? Oh yeah, and does it have audio grouping...?

SBowie
05-17-2012, 12:22 PM
What is the upgrade cost from a 450 to 455? Oh yeah, and does it have audio grouping...?I don't really know (sorry), and yes (audio grouping).

Correction - Upgrade pricing (https://shop.newtek.com/index.php/tricaster?page=shop.product_details&flypage=flypage-vmshopblue.tpl&product_id=532&category_id=1)

spotduster
05-17-2012, 12:57 PM
Well, we'd love to upgrade, and eventually probably will, but funding is hard to come by for us. So I guess for now we'll hope for a software update fix for our 450. Since the recordings are out of official specs we think a fix isn't too much to ask for. It's a pretty minimal fix anyway.

Andrew offered for Beta testing,... how do we sign up for that? If this is fixed in a beta release soon, we'd love to get back on loss-less work flow asap.

SBowie
05-17-2012, 01:11 PM
Since the recordings are out of official specs we think a fix isn't too much to ask for. It's a pretty minimal fix anyway.When it comes to codecs, I'm afraid there's no such thing as a 'minimal' fix. Every little tweak can have unforeseen consequences, requiring a lot of planning and testing, quite apart from implementation. The sad fact is that it's actually unusual to find apps that support standard specs in every detail, which is why compromises are 'de riguer'.


Andrew offered for Beta testing,... how do we sign up for that?It will follow from the existing case, I'm sure, if/when there's some movement on it.