Is there a bug with MainConcept rendering?

DazGsy wrote on 3/8/2013, 10:26 AM


Hi all,

I've put hours into this and still not solved it. Basically, I have two problems with MainConcept AVC/AAC rendering in Sony Movie Studio 12 64-bit:

1) Rendering using VBR CUDA (NVIDIA GeForce GTX675M), I am getting blockiness/pixelation in one scene of my video, which actually looks like half a second of residual image from the previous busy scene. Makes no difference if I used single-pass or two-pass, or even increase the max bitrate to 16Mbps. But at least this render uploads to YouTube OK without any strange warning messages from YouTube. However,

2) Rendering the same MainConcept template, using either:
(a) CPU rendering, VBR & CBR
(b) CUDA rendering with CBR
...the render looks great, BUT if I try to upload any one of these to YouTube, YouTube gives me the message: "We see irregularities in the aspect ratio of your uploaded video" and when YouTube publishes the video, the 720p version has an identical resolution to the 480p version!

Running MediaInfo on all renders shows that they are 1280 x 720 as they should be.

This has fried my brain! Please can anyone help? Thanks,

Here are my render settings:

MainConcept AVC/AAC
Frame size HD 720 (1280x720)
Allow source to adjust frame rate: No (not checked)
Profile: High
Frame rate: 25.000 (PAL)
Allow source to adjust frame rate: No (not checked)
Field order: None (progressive scan)
Pixel Aspect ratio: 1.0000
Number of reference frames: 2
Use deblocking filter: No (not checked)
Using CBR, bitrate = 10Mbps
Using VBR, I tried Max 16Mbps Average 8Mbps, and Max 10Mbps Average 8Mbps
Enable progressive download: Yes (checked)

Windows 7 64-bit (and 64-bit Sony Movie Studio 12)
Intel Core i7-3610QM


c3hammer wrote on 3/8/2013, 2:05 PM
It's working for me, but you need to go to the project tab and set Video Rendering Quality to "Best". For some reason if it is set to "use project properties" tab it gives goofy results.

DazGsy wrote on 3/10/2013, 7:16 PM
Thanks for gettings back to me Pete. I tried setting the rendering quality to "best" in the rendering settings but it made no difference.

I do have some 4:3 clips in my 16:9 720p video, so maybe YouTube is picking up on those, but I've had no problem doing this in the past, and it only seems to be with certain MainConcept render settings.

Hmm, in the past my 4:3 clips have been progressive, whereas this time I am de-interlacing (blending). Maybe that has something to do with it, or maybe YouTube are reprogramming their system, or there's a problem with MainConcept in Movie Studio 12. I'm all out of ideas.
mikerb wrote on 3/10/2013, 7:48 PM
I have a very similar PC set up and use MS v12....and I mainly use mainconcept albeit at 1080 rather than 720....and I have had no problems. I think you may be right however in terms of the 4:3 clips. I do not fully understand how you are coping with a mix of progressive and interlaced footage. I assume you have set your project in a similar way to your render settings which is not going to do much for the 4:3 clips. I transcode all my footage before going into Vegas but I do know that Vegas will automatically change 4:3 to 16:9 if that is how your project is set. I suspect you may have to render the 4:3 footage separately and then reimport that to your project.
DazGsy wrote on 3/10/2013, 9:06 PM
Thanks Mike, I think that's a good suggestion about rendering the 4:3 footage separately then importing into my 16:9 project. I'll give that a try tomorrow using AVI uncompressed so I don't degrade the quality.

I've learned a bit more about the problem:

1) YouTube is now giving me the warning "..Irregularities in aspect ratio" when I upload the MainConcept VBR CUDA render (previously, YouTube had been happy with this render). So now it seems that YouTube has problems with ALL of my renders using MainConcept... but this could just be when de-interlacing 4:3 clips in my 16:9 720p video... I'll have to experiment more.

2) Whenever I get the "Irregularities in aspect ratio" from YouTube, the final processed video on YouTube has a slightly changed aspect ratio (I only found this out by taking and comparing screen snapshots). So even though MediaInfo says my video is 1280x720, YouTube doesn't think it is, and is changing my video aspect... hence the rubbish 720p quality on YouTube.
DazGsy wrote on 3/11/2013, 10:57 PM
There is definitely a bug with the MainConcept MP4 HIGH profile that affects the aspect ratio of the rendered video. I've only tried this with 1280x720 so far, but it might also affect 1080p.

You can test this quickly by creating a new 720p project, importing any photo or short video clip into the timeline and rendering to MainConcept MP4 with a HIGH profile (Baseline and Main profiles are fine). Choose CPU rendering with either VBR or CBR. Note that Rendering using the combination of VBR & CUDA will be OK most of the time but not all of the time.

The proof of the incorrect aspect ratio of the render can be seen by either:
1) uploading to YouTube, where YouTube will compain about "Irregularities in aspect ratio", or
2) by viewing on a modern TV that has the "Fit to Screen" display option. You will see that the rendered video has black bars at the sides.

I'd be interested if somebody else could try this. I'm really disappointed because MainConcept seemed a little sharper than Sony AVC.

musicvid10 wrote on 3/12/2013, 10:35 AM
Please do a short experiment to confirm your observations.

1. Render a short segment using Mainconcept that shows the incorrect aspect. Post a screenshot of the default advanced render settings that were used.

2. Render a short segment that shows the correct aspect (MP?). Also post a screenshot of the advanced render settings.

3. Upload both rendered samples to a sharing site (Mediafire, Dropbox, Google Drive), but not to Youtube and post the links here.

With this information, it should be possible to determine where the error is occurring, and you can share that information with Sony when you file your tech support ticket. It will be most helpful to know if MC is rendering the pixel aspect incorrectly or merely flagging it incorrectly.
videoITguy wrote on 3/12/2013, 3:11 PM
Musicvid, just to add to your point - flagging within metadata is a two-way street - It has to be written and interpreted. These functions are the responsiblity of both the authoring app and the interpreting app.
And to make matters worse, these standards are not exacting.
DazGsy wrote on 3/13/2013, 7:38 PM
Thanks for your responses. Musicvid, my detailed render settings are in my first post. Unfortunately I can't put any more time into playing with this fault, but as far as I can tell the problem can be replicated simply by rendering MainConcept AVC MP4 using HIGH profile and then either uploading to YouTube or playing on a TV that has the "Fit to Screen" display option.

I've opened a support ticket with Sony and given them all the details, I'll let you know the outcome.

c3hammer wrote on 3/13/2013, 7:50 PM
Is there some reason folks don't just use the Sony AVC/MVC mp4 render? I think it produces better results than MainConcept anyway.

I've never had any issues with it when going to Youtube from a 1920x1080 file at 26 mbps. These files when viewed over wifi via youtube on my 55" panasonic lcd are simply outstanding and hard to believe they can have come from a $600 DSLR and a $400 GoPro.

DazGsy wrote on 3/13/2013, 8:42 PM
Hi Pete,

I used to use Sony AVC but after upgrading to Movie Studio 12 I noticed that the Internet AVC MP4 templates had been moved from Sony AVC to MainConcept AV, so I did a load of test renders with Sony and MainConcept using the same bitrates and settings and compared them using screen grabs (screen snapshots) at various points. I found that when my video had a lot of movement, MainConcept gave me slightly sharper images with less artifacts around areas of detail. But then I'm rendering at between 8 and 16Mbps, not 26Mbps, so things might be different at your bitrate.

So unfortunately I can't use MainConcept with a 'High' profile because of the above problems. I'm also getting occassional strange results when rendering MainConcept using my GPU (NVIDIA GeForce GTX675M), so my current render choices are:

1. Sony AVC using CPU or GPU (fastest render, quality not quite as good as MainConcept)
2. MainConcept, 'Main' profile, CPU (best quality but REALLY slow to render)

musicvid10 wrote on 3/13/2013, 9:16 PM
"Unfortunately I can't put any more time into playing with this fault, but as far as I can tell the problem can be replicated ... either uploading to YouTube or playing on a TV that has the "Fit to Screen" display option."

Youtube tells nothing about your rendered file pixel aspect or metadata, because it has all been reprocessed. "Replicate" is not even close to what I asked for. I find it a bit annoying when people come here looking for peer support, and then suddenly find themselves too busy to provide the relevant information being sought.

Tech will likely ask you for original rendered clips, as I did. Please don't tell them to look on Youtube.
DazGsy wrote on 3/14/2013, 8:28 PM
Musicvid: I wasn't suddenly too busy to provide the relevant information, it's just that what you asked for was a bit overwealming when I've never even used Dropbox, Mediafile or Googledrive.
I thought it would be much quicker for Sony Support, or any interested reader, to render just 10 seconds of a single JPEG photo using the render settings listed in my first post than it would be for me to learn how to use Dropbox or Googledrive. But if sample videos on a sharing site is what's needed, then that's what I'll do.
musicvid10 wrote on 3/15/2013, 12:21 AM
I suggest you wait for a response from Tech, but don't wait forever.

I can see my earlier post overshot the mark; but if you are going to edit video, it would be advantageous for you to be just a bit more adventurous.

Signups for any of those services are free and the interfaces are intuitive (drag 'n drop). I use Dropbox a lot because of its ease of use.
DazGsy wrote on 5/2/2013, 4:22 PM
Just an update for anybody with the same trouble: I got a response from Sony today (after nearly 2 months). They managed to recreate the problem, and said:

"MainConcept 4, although it can work on youtube, sometimes does have issues like these"

... which is interesting seeing as MainConcept is now the template for 'Internet' rendering! They advised me to use Sony AVC, which is what I decided to do a couple of months ago anyway.

I see there's a new build available now, BUILD 896 64-bit. I will try this soon. I'm sure this will fix some old bugs... and introduce some new ones :)

Here's the full response from Sony:

Hi ,

Thank you for contacting Sony Creative Software. I apologize for the lengthy response time to your technical support inquiry. We have been experiencing an increase in support demands from new product launches and we have fallen a bit behind on service requests. We have been working diligently to answer as many emails as possible in the order that they were received. I hope you understand and sincerely appreciate your patience.

I have simulated this behavior on my machine and spoken with our techs on this particular aspect ratio issue. It seems to be intended behavior with the format with this output. When you are telling it to fit to screen you are telling the device, whether youtube or your television to change the dimensions to fit because those dimensions are not 1280x720. For youtube we actually recommend rendering to a 1920x1080 as it is closer to the youtube dimensions. MainConcept 4, although it can work on youtube, sometimes does have issues like these. We would recommend using either the Sony AVC/MVC MPEG-2 format or WMV, but it appears you are already using this format without running into this issue.

If you still have a follow-up question on this particular incident, please feel free to update it. If you have a completely different question, please create a new incident.


Kim N.
Customer Service
Sony Creative Software Inc
TroyTheTech wrote on 5/5/2013, 3:04 PM
" far as I can tell the problem can be replicated simply by rendering MainConcept AVC MP4 using HIGH profile..."

This is exactly what happened to me, with Mainconcept's AVC profiles:

There is some 'bugginess' to MC-AVC and how it is implemented in Vegas. At least I can use Sony's AVC just fine, with any settings as all.

Great to see their acknowledgement of this FINALLY..... Thanks for letting us know what they said, Daz.