A friend of mine has sent me some files on disc from his HDV camera (Canon XH-A1). He imported them into a recent version of Studio and exported them as MPEG2 .MPG files.

Playing them in VLC Media Player, it tells me that the video is MPEG2, 1080x1440, 50 frames (that's actually interlaced fields, not true frames, I guess), 4:2:0 and the data rate fluctuates around 25000 kbps, which is exactly what one would expect for HDV2 footage.

When I import these files into AL7.2, the clip properties agree with what VLC says except that the bitrate is shown as 35 Mbits/sec. The reason I care about this is that when I fuse the finished sequence (to author a Blu-ray Disc in TMPgenc AW4), Liquid insists on re-rendering these clips which always results in some loss of quality and occassionally makes a pig's ear of it!

I don't get the same problems when I import files from my Sony MRC1 CF-card recorder. They are M2T files rather than MPG. I notice that VLC says that in the MPG files, "Stream 0" is audio and "Stream 1" is video, whereas in the M2T files, "Stream 0" is video and "Stream 1" is audio.

Has anyone else encountered this problem and if so, how did you get around it?

Is there an effective way to convert .MPG files to .M2T? Is it "harmless" with no re-rendering?

Thanks in advance

I realise that VLC is able to convert between various formats, including changing MPEG2 Program Stream to Transport Stream, which I think is the important difference between .MPG and .M2T. However, this hasn't had the desired effect:

• The converted file jumps when played in AL7.2
• The clip properties still say 35Mbps and the video appears to be re-rendered during Fuse 

Maybe VLC doesn't do the conversion very well?

Maybe the original file contains incorrect meta-data, making AL7.2 think the data-rate is faster than it really is?

35Mbps MPEG2 is one of the standard Sony formats, as used in the EX1, isn't it? XDCAM??

(By the way, it's nice to find this forum is still up and active, though a little quieter than in former days.)

Looks like the mistake is in the original MPG files created by Studio. I imported one into a TMPgenc Authoring Works project and checked the clip properties there. It also thinks the bitrate is 35000 kb/s. I guess the mistake is in the meta-data or file labelling, since VLC shows the data rate it is actually receiving and displaying - 25000 kb/s.

Does anyone know of a program that lets me edit the meta-data without touching the actual video and audio content?

Maybe-

 http://tmpgenc.pegasys-inc.com/en/product/tmsr4.html

I'm trying VLC Media Player's "Convert" function, but so far without success. Specifying 25000 kp/s gives a file that AL7.2 thinks has a bitrate of 106Mbps! Surprisingly, it imports and plays the file OK. Unsurprisingly, Fuse fails on the first frame!

I have had similar problems using the Aunsoft converter to make mpeg2 files. Fail to fuse or render. Someone I talked to the other day had similar problems with mpeg2's from Sorenson. Seems like Liquid does not like those converted files for some reason. Sad to say, but I think Liquid's time has passed. In order to use Aunsoft and be able to render the files I resorted to DivX AVI files. Then I moved away from Liquid to another NLE.

LewS:

I have had similar problems using the Aunsoft converter to make mpeg2 files. Fail to fuse or render. Someone I talked to the other day had similar problems with mpeg2's from Sorenson. Seems like Liquid does not like those converted files for some reason. Sad to say, but I think Liquid's time has passed. In order to use Aunsoft and be able to render the files I resorted to DivX AVI files. Then I moved away from Liquid to another NLE.

In the long term, you're right, Lew, but that's a big investment both of time and money which I can't really justify until I change to a camera that AL can't cope with. However, I have a project on the AL7.2 timeline this evening and some MPEG files I want to use in it. Liquid will deal quite nicely with most of the files, it just makes a mess of rendering three particular clips when in theory there's no need to render them in the first place.

This evening I tried downloading AnyVideo Converter (as mentioned in another thread) but cannot find a way to create an MPEG2 output with a bitrate higher than 9800 bps (or is that kpbs? It's not clear) nor a way to simply copy the audio stream without transcoding it, so I've uninstalled it already. There seem to be dozens of video format converters out there, but I wonder which of them will give me the control it looks like I need?

When my friend gets back from the States, we'll try to export a file from Studio that Liquid will accept

Just in case this rings any bells with anyone, here's what I've discovered so far:

I've used MediaInfo to look at the MPEG parameters associated with the video stream in various files. The significant difference between files that work OK (including AL fuse outputs) and the ones that give trouble appears to be the BitRate_Maximum/string setting. In the good files, it's "25.0 Mbps" whereas in the files that give trouble, it's "35.0 Mbps". This is in contrast to the BitRate/string parameter, which ranges between 24.4 and 25.3 Mpbs in the files that work OK, and is 24.9 Mbps in one that gives trouble, and which appears to match the numbers displayed by VLC when I play the files.

It appears that what I need to do is reset BitRate_Maximum to "25.0 Mpbs", ideally without re-encoding the video nor the audio.

I mentioned that I had problems with 2 files re-encoded using VLC. MediaInfo shows what the problem might be: BitRate_Maximum is empty/blank. Everything else looks normal, compared with the other files. This reinforces my theory that BitRate_Maximum is the thing that both AL and AW4 are relying on.

The good news is that I have found a program, called ReStream, that edits MPEG2 video-stream parameters. You have to de-mux programme- or transport-stream files first, but it successfully changed the BitRate_Maximum parameter, so that AL7.2 and AW4 reported the files as "25 Mbps". Both programs imported and played the "fixed" file with no issues.

The bad news is that this doesn't make any difference to Liquid when I fuse a sequence containing the "fixed" footage. It still re-encodes it, and it still makes a mess of the same bits. So back to the drawing board, and almost certainly back to the original Studio import/export. I've been looking very closely at all the footage over the last few days, and I've realised that Liquid is just exaggerating faults that were already present.