I have a couple of observations about Media Composer (still on 5.5) and rendering.

I noticed that on a very simple project (1080p/25 - DNxHD 185 and Titles 1:1 MXF)  I'm working on that once the timeline is exported as a QT Ref then the timeline is rendered as expected, all the effects were real-time playback effects and apart from a few effects at the end it played back smoothly but I noticed that once rendered the playback is actually worse than before it was rendered. Most of the issues seem to be on cross fades particulary at the beginning on Titles, Video and audio freezes playback and continues a few frames down the timeline.  Would this be normal? If I delete the renders and clear them using the Media Tool, it goes back to better performance.

Also I find that after a render some clips have red lines across the top of some clips, especially near transitions, so it seems to be related to the above observations.

Any explaination of how Media Composer rendering works would be useful, I can only go by Liquid on a P4 machine but with only SD footage but once rendered the timeline playback was generally smooth.

Dean 

Dean,

A 1080/25p and at DNxHD 185 resolution a project can't be very simple...

It is normal as the timeline is a heavy one.

Even reading... renders at this stage it needs much power.

The red line means that its not fully rendered - so that may have something to do with it. I've noticed that unrendered material will stall when it it plays over clips edits.  

Did you have all the tracks turned on and use a full render or a smart render?  

Another thought - if he red lines appear after the playback, that may indicate playback issues.

Have you checked your drive capcity?

Just thiking out loud - I run into this a fair bit running HD materai

Dean Murray:

Also I find that after a render some clips have red lines across the top of some clips, especially near transitions, so it seems to be related to the above observations.

Are you marking the entire timeline, all tracks active and using "render in/out"? If not, try that. The red line above the clips indicate unrendered regions. In my experience, I have found expert render to be sometimes unreliable.

What resolution are you rendering at?  Check your media creation settings, on the render tab, do you have Same as Source checked? 

What I think may be happening is that you are rendering at 1:1. Uncompressed HD is much harder to play back real time than 185. If you are saying rendered dissoves and such are not playing back, then this must be the case.

Confirm that you are rendering at 185, and uncheck Same as Souce, that way your titles that are 1:1 will now render at 185. Thus it will give you better play back.

Yes i agree with mr difficult, it does sound like your render is at HD uncompressed and your storage cannot deal with that.

Thanks for all your responses. 

Thanks to all your comments I think the issue is that my storage has problems with the uncompressed titles, so I thought I'd try and save some of the titles as DNxHD 185 (I used Marquee) but couldn't find a way to do this, as loading the title and saving back to a bin seems to retain the 1:1 MXF format.

So is there a simple way to re-save the titles in a different format or do I need to recreate them from scratch?

Also another question about the source Canon footage, I think I read a post from George saying that DNxHD 185 was probably too high and DNxHD 120 would be ok, what are your thoughts on this?

Oh yes not using Expert Render did render everything with no residual unrendered elements,  so is Expert Render the default when a segment is exported?

Thanks again

Dean

Dean Murray:

so I thought I'd try and save some of the titles as DNxHD 185 (I used Marquee) but couldn't find a way to do this, as loading the title and saving back to a bin seems to retain the 1:1 MXF format.

Go into the media creation section of your user settings, where you can set the resolution and disk destination for each different type of media and go to the appropriate tab.

Dean Murray:

So is there a simple way to re-save the titles in a different format or do I need to recreate them from scratch?

Yes. Select all the title clips in the bin and delete ONLY THE ASSOCIATED MEDIA FILES, NOT THE MASTER CLIPS. Then, from the clip menu, choose "re-create title media".

Larry Rubin:

Go into the media creation section of your user settings, where you can set the resolution and disk destination for each different type of media and go to the appropriate tab.

Thanks I've made the changes and it worked fine.

Larry Rubin:

Yes. Select all the title clips in the bin and delete ONLY THE ASSOCIATED MEDIA FILES, NOT THE MASTER CLIPS. Then, from the clip menu, choose "re-create title media".

This one was a little more problematic, I followed your instructions and ie: "Delete 3 associated media files" and the two "Resolutions to delete" and from the clip menu used the "Create Unrendered Title Media..." which created the DNxHD 185 media.

I then cleared the renders on the timeline and re-rendered the offending area and was told "Media Offline" so I replaced all the titles with the newly created ones in the bin.  Did I do anything wrong?

Anyway the good news is that the rendered timeline plays perfectly and I understand a little bit more about Media Composer.

Dean

No, you didn't do anything wrong. Since you needed to change the resolution,to prevent clutter and duplication, you either delete the existing media files, which create a media offline condition, or transcode the existing clips in the timeline to a different resolution. Having done both, I find the first option faster than transcoding. If you don't mind having duplicated media files on your system, you could leave the original titles online and then use "re-create title media" to create new media files at a different resolution.

Hi Larry,

Sorry to ask possibly a silly question but from what you explained,  I needed to replace the titles as I did?

Is that correct?

Dean

Not replace the titles as such but the media that allows them to playback.

Unless you have imported files with mattes or have mixdowns my prefered choice is to delete renders (or use MDV to move them offline in case I need one back later!)

The re-render and re-create titles after ensuring the media creation settings are all correct.

Dean Murray:

I needed to replace the titles as I did?

You did not need to physically replace the titles in the Sequence from the Bin.  

On a sample seq, create two Titles both at the same resolution.  

Mark In/Out so that only one of the Titles is encompassed.

Set your Media Creation settings for Titles appropriately to change the resolution

Choose Re-Create Title media.

You'll see that the one title between the marks will be changed to the new resolution, the other will be untouched.  

Pat Horridge:

Not replace the titles as such but the media that allows them to playback.

Unless you have imported files with mattes or have mixdowns my prefered choice is to delete renders (or use MDV to move them offline in case I need one back later!)

The re-render and re-create titles after ensuring the media creation settings are all correct.

Thanks Pat,

Following Larry's tips I removed and recreated the media in the bin and not on the timeline which I think is where I went wrong but thanks to Kenton's post too it's all a bit clearer now, although I assumed (I know I shouldn't) it would update the timeline too.

Dean