Lossless joining of AVCHD clips - 720p60
 

Just curious to know what tools folks like for joining AVCHD clips without recompressing them.

I've been using Corel VideoStudio Pro X3 for a while, as a stand-in for Adobe Premiere, because of how well it works with AVCHD, particularly with regard to needless recompression of unmodified clips. When shooting in 1080i60, VideoStudio is a miracle. The trouble with VideoStudio is that its "smart-render" function doesn't work well with 720p60 footage, something I've lately been producing a lot of. VideoStudio happily ingests the 720p60 and spits it out as quickly as ever, but with major audio/video sync issues after the first cut.

I've also tried tsMuxeR. The tsMuxeR GUI advertises a "join" function, but regardless of 1080i60, 720p60, etc., the result has subtle audio/video sync problems that can become very non-subtle after several cuts. I don't get the feeling that joining .m2ts files is something tsMuxeR was really designed to do, but rather something that the author of the GUI wrapper app decided to bolt on later. Doesn't work for me unless I'm only joining two or three clips.

Anything else? I understand (or have heard) that Vegas Movie Studio and some of the other lower-cost NLEs can smartly render AVCHD. The trouble is that so many of the trials have this stuff ripped out due to licensing constraints, making it difficult for me to test this out with my footage and see if it works.

Best,
Aaron

Aaron:

I regret to say this but I do not understand what exactly are you doing in your post: are you asking, suggesting, or sharing?

If you are simply asking how to merge AVCHD clips without recompressing them in the process, then my answer will be use Sony Vegas Pro.

In Vegas Pro 9 (I believe, in the version 10 it holds true), in order to perform rendering without recompression, the width, height, frame rate, field order, profile, level, and bit rate of the source media, project settings, and rendering template must match.

In other words, if you opened AVCHD clips recorded in the 720p60 format in the project, whose width and height are 1280 and 720 respectively, and frame rate is 59.940 (i.e. double NTSC), and afterwards chose to melt them down into a M2T-type file using the template with the same width, height and frame rate, then the rendering process would go without any recompressing.

You can test this for yourself; just download the trial version of Vegas Pro 10. Once activated, the software becomes fully functional for the duration of 30 consecutive days.

Hi, Arkady:

It was all in the first line. :) I am interested to know what people are using to do this. Everything else in the post was about the problems I have faced with what I am using.

Yes, that is indeed all I am trying to do. I'll give the Vegas 10 trial a go. I was never successful in getting this to work in Vegas 9, although it is certainly possible that I missed a single setting that made the difference. One of the things I love about Corel (which is why I sooooo wish it worked well with 720p60!) is that, when rendering, you can choose things like "Same as first clip," or have it auto-choose for minimum recompression with "MPEG Optimizer." Really a great idea, but alas the A/V sync issues with 720p60. :-(

Best,
Aaron

Hi Aaron,

100 percent agree with what you said about the Corel recompression. I wish the Vegas had the same thing...

Regarding Vegas Pro suite, the most tricking part (in minimizing or avoiding at all the recompression) is to deduce the right bit rate of your source media. Just typing 24 Mbps into the filed, which provides the maximum bit rate of the rending template, sometimes is not enough: you should know the maximum bit rate of your source precisely.

For that purpose, I recommend MediaInfo free software: it will give you the detailed and elaborated information about your source video codec, aspect, fps, bitrate, etc.

That's good to know. I'll give MediaInfo a shot together with Vegas 10. It's quite possible that I tried 24Mbit/s figuring that anything there or lower would make it through unscathed. I generally use AC3 audio and not PCM, however, so the peak will be somewhat lower (~22Mbit/s, I believe).

Thanks!
Aaron