X3 AVCHD crossfade blocky

[meinthecorner]

Source Files

PAL HDMV
Type: H.264 Video Upper Field First
Attributes: 24bits, 1440 x 1080, 16:9
Frame: 25
Date Rate: Variable (Max 12000)

Using the Share option and then, Create video file, AVCHD > PAL HD 1440

The file is created fine, its only a small 2 min test file with 4 Crossfade Transitions, but these are very blocky between scene fades.

When I select the PAL HD 1440 the Mpeg Optimizer pops up showing the Green segments for the original files, then the red parts from the transition area's.

Any suggestions? If I encode the file to plain DVD Mpeg the transitions are smooth.

[Ken Berry]

Disable SmartRender and see if the blockiness remains. To do this, when you select Share > Create Video file > AVCHD, then in the dialogue screen which appears, you give your new file a name, then click on the Options button and uncheck 'Perform SmartRender'.

[philip_l]

Hi

I've seen this problem. It is due to the low quality and data rate the transitions are encoded. Cross fades are particularity tricky to encode.

Not using Smartrender may help if you up the quality settings to maximum.

Also under File-Preferences-Edit make sure Resampling quality is set to Best.

Regards

Phil

[meinthecorner]

Thanks for the replies. Unfortunately nothing seemed to stop the blocking up. I've removed the cross fades for the time being.

I did notice that encoding as a xvid file at 1280x720 had a perfect transition.

[philip_l]

Hi

The only reliable way around it is to render out as something else. For example I'm just rendering out a project in a lossless format which means transitions are created without any compression artefacts then use a third party encoder to get DVD and AVCHD out. Cross fades are then just perfect although it all takes much longer.

The main issue I think is the AVCHD compression settings in VS seem to have a low average bitrate which you can't seem to change and this low average effects any complicated scenes needing re-encoding, including crossfades.

Regards

Phil

[meinthecorner]

When you say Lossloss format, can you say what format \ settings etc you are using?

[philip_l]

Hi

The lossless format is http://lags.leetcode.net/codec.html. You could try rendering out using this format (you select Share->Customer->Microsoft AVI->Set the Field order and resolution correctly, then on the Compression page select the Lagarith Video Codec.

File sizes are big but you can use this file in any third party encoder to compress down to your target format.

Regards

Phil