Flushing transcoder buffer

[Nicholas Rumin]

I am using Ulead Version 10 to capture video from a Sony digital camcorder.
In video capture (MPEG2) the capture usually ends abruptly before the specified duration (10 to 20 minutes). I then get the "flushing transcoder buffer" message and the flush typically takes 5 to 10 minutes. The amount of data being flushed is typically 7000 ? The last time this happened the program froze during the flush and I lost all the captured video. Why does this happen and what should I do to avoid it?
I am following the capture formats recommended in your very good tutorial.

[Ron P.]

I would suspect that you're computer is not keeping up. Since you are capturing from a DV camcorder to MPEG-2, it must convert it "on the fly". How many processes are running when you are capturing? You need to have the absolute minimum, so that your PC can devote all the resources it can to your capturing.

I would try just capturing (transferring) your video in DV.

[Ken Berry]

Привет Николай! I am afraid I have to agree with Ron. Looking at your computer, I would normally say it was capable of capturing direct to mpeg-2 from a mini-DV camera, but you can never be certain until you try it and it works. So try it again, as Ron suggests, with all unnecessary background processes turned off. Disconnect from the internet to, and that way you can safely turn off your anti-virus program too.

Essentially, though, capturing direct to mpeg-2 like that is very demanding of computer resources. The data comes flying into the computer in DV format, where it has to be converted in real time to mpeg-2, which is not a simple process. If the computer is not able to devote a lot of resources to it, it begins to slip behind, and the information waiting to be processed gradually builds up in a 'transcode buffer' (i.e. waiting to be transcoded from DV to mpeg-2). Eventually, though, the buffer will be full, so the capturing has to be stopped to prevent any more information coming in as there is nowhere left to store it. Then the information already in the buffer has to be processed first and the buffer emptied, so that more space is available for new information. And as you have found, that means the capture will just stop, and rarely will it stop at a spot in the video where you would want it to.

Capturing to DV format first, on the other hand, places no strain on the computer at all since it is capturing in exactly the same format as the video in the camera, so no extra resources are needed for any conversion, and there is no buffer to fill up. In effect, you are simply transferring the video in the same format to your computer.

That is the major reason we recommend that when using a mini-DV camera, capture to DV, do all your edits in DV, and only then go to Share > Create Video File > DVD to convert the DV to DVD-compatible mpeg-2. The end quality usually is such that you won't really mind losing that extra time in the conversion...

It also avoids potential problems that very definitely can arise when you try to edit mpeg-2.

[Nicholas Rumin]

Spasibo, Ken, and thank you Vidoman. As a matter of fact I did do all that you suggest: disconnect from Internet, stop real time virus catching, stop background processes, etc.
I understand that the buffer can reach capacity but I would expect the software to then clear the buffer and end the capture gracefully. Causing the computer to freeze and losing the captured video is not graceful.
I used to capture in DV when I used MyDVD , but it really gobbles up disc space. When I read your tutorial advocating capture in MPEG2 I decided to switch to that mode and, as I wrote, most of the time the transcoder buffer is cleared gracefully.
You mention possible editing problems in MPEG2. What do you have in mind? I have not experienced any except when I mix clips captured in DV with ones captured in MPEG.

[Black Lab]

I used to capture in DV when I used MyDVD , but it really gobbles up disc space.

Were you capturing uncompressed DV (65 GB/hour) or DV-AVI (13 GB/hour)? DV-AVI is still more than MPEG-2, but it would eliminate your problem.

[Ken Berry]

uncompressed DV (65 GB/hour) or DV-AVI (13 GB/hour)

Just to clarify: it is of course uncompressed AVI which takes 65GB, and DV/AVI which takes 13 GB.

As for possible problems editing mpeg-2, the most common one, experienced by a wide range of users, is out of sync video and audio, particularly if SmartRender could be used -- as it can be if you capture in mpeg-2 then edit in the same format, and render a new mpeg-2 from it.

Capturing DV is still IMHO the best format to capture from. I realise that space may be a consideration, but hard disk prices have plummeted in the past year or so and you could always add a new one to your computer, or insert one in an external hard drive case.

[Black Lab]

Thanks for clarifying, Ken.

[Nicholas Rumin]

Spasibo Ken and thank you Black Lab. Yes, when I captured in DV it was DV-AVI.
Your comment re editing in MPEG2 is very useful. I did experience out of sync video and audio once, but that was on a segment captured from a PAL DVD in MPEG2 and mixed with other segments, some captured from my camcorder in DV-AVI and then coverted to MPEG2, with the final project converted again to MPEG2 before burning .It was especially noticeable on a segment of my granddaughter playing Bach on her violin !

IMHO??

[Ron P.]

IMHO = In My Humble Opinion..