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AVCHD re-encoding?
Hello All,
I have AVCHD source files in Sony Picture Motion Browser (PMB) from my Sony HDR-CX12. When I render the AVCHD disc in PMB it looks perfect — just like I played it back directly from the camera. However, PMB lacks any real editing tools so I import the media into Vegas Pro 10, edit away the badness and render the files into different formats. Any attempts to render result in poor quality (blurry/jerky). I’ve even tried rendering to the Sony AVC template as AVCHD 1080-60i (which matches the source) which created a .m2ts file. This is the same format as the source file. If I import that back into PMB and burn to AVCHD disc it looks blurry.
So, if the source file is .m2ts, and it burns to AVCHD disc perfectly in PMB, what is Vegas Pro doing to its rendered .m2ts to make it look so blurry? I would think there is a non-reencode option since the source format matches the render format.
NOTE: it’s poor even before re-importing into PMB so that doesn’t look like the issue to me.I realize there are a number of specifics I’ve left out so rather than type out potentially unimportant details I’ll answer any questions as requested.
Thank you for any assistance!
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2 Replies
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Re-encoding is always going to deliver a slightly lower quality result. What bitrate are you shooting on the Sony? The maximum bitrate on the CX12 is 16Mb/s. Technically speaking, AVCHD on DVD has to be 18Mb/s or lower, so the motion picture browser is probably just copying your camcorder files to DVD. Basically, if you take the AVCHD structure from your flash card and drop it on a DVD in UDF 2.5 format, you have yourself an AVCHD-DVD. It’s not legal to go over 18Mb/s on DVD, but you won’t have that issue.
Sony’s default “AVCHD 1920×1080 60i” template is also rendering at 16Mb/s. And no, there’s no “smart rendering”, as Sony calls it, for AVC yet – which would apply if you shot at top quality.
You should double-check, at least, that you’re actually using that template. Check the “custom” settings, and you’ll find the bitrate used for that particular output preset. I know for some of the format, Sony has some oddly low bitrates, like 8Mb/s for full HD.
Another thing.. in the project preferences, there are several settings that can have an effect on output quality. Specifically, set render quality to “best” and pixel values to 32-bit (video levels). Your output may all of a sudden look better.
-Dave
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Thanks. I am absolutely recording at the highest quality, and the encoded m2ts files all seem to display around 15,000 and some change for the bitrate. It’s odd to me, that Vegas has to re-encode the file when lower-end applications like Corel Video Studio Pro X3 are smart enough to display the segments of the timeline which will not require re-encoding right before the render. To be honest, the output from Corel is remarkably higher quality and to me it looks like I hooked the camera HDMI directly to the TV and played it back that way.
Perhaps I muffed the Vegas params — there certainly are more to fuss with. I will try the suggestions you mention to see if the quality improves.
As an aside, do you know if the Corel app is doing something to deinterlace the source files that I might be omitting in Vegas? I keep reading about the deinterlace process in Vegas but guess I don’t understand how to do it… it’s quite possible I’m looking right at it and don’t know I suppose. I know it made no difference to change from Upper First to Progressive, and I think that might be because the TV handles the deinterlacing automatically on the fly.
Thanks again for the tips! I much prefer the Vegas interface so let’s hope this helps!
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