Smart Rendering H.264 (Sony Vegas 9)

[pigmonkey]

I have a H.264 file that was given to me from a friend, and I am trying to edit it alongside my raw uncompressed video. I have the H.264 fading in and out so that it effectively "switches" between the videos when I want. When I render (using a multipass render), it skips the entire part of the full H.264 video as expected saying "No Recompression Required" as expected. However, when I try to view the final video, it starts acting glitchy as soon as it gets to the point in the video where that message came up, as if it didn't correctly put it together. Sometimes the video freezes completely and resumes later, sometimes there are green and red artifacts showing up, and then when it gets to the end of the clip and starts playing the newly-rendered video again, the same problems come up.

To debug, I even took my own clip, rendered it, and then put the rendered version back into the project to ensure that the output settings were the exact same. I am still experiencing the same problems. I don't know if H.264 is just a codec that doesn't work well with smart rendering, or if I need to continue to mess around with the 50-some vaguely labeled options that I left on default until I see some improvement.

If anyone has any experience or suggestions in the matter, it would be appreciated. I am trying to avoid re-rendering, as there is a quality loss.

[edDV]

Unless something was added in the Vegas version 9e update, h.264 is not supported for smart rendering.

see
https://forum.videohelp.com/threads/317766-How-to-smart-render-a-VBR-in-Vegas?highlight=smart+render+vegas

[poisondeathray]

Maybe he means specifically AVCHD, which is supposed to be supported.

In my tests , it sometimes works (rarely), but sometimes very buggy and not very stable. You do get the "no compression required" sign, which he indicated, but the results are more often garbage (at least for me). Apparently some users have reported limited success

[pigmonkey]

I actually don't know what I mean. I'm fairly new to the specifics of rendering. All I know is that I'm rendering it as a Video for Windows (*.avi) using "x264vfw - H.264/MPEG-4 AVC codec" as my video format.

[poisondeathray]

It doesn't export x264vfw with smart rendering, nor does it support generic h.264 formats as input for smart render

smart rendering only works with supported INPUT formats (there is a list on their website), and the EXPORT settings have to be identical. And even then, it usually doesn't work very well. The only (supposedly) supported h.264 format is AVCHD, which is a subset of h.264

[pigmonkey]

That's basically what I'm looking for; thanks for clearing things up.

[edDV]

For smart render to work at all the source, project and export formats need to be identical. Essentially the source input GOPs get copied to the output file. Only GOPs that are changed get rendered.