Gaps between .m2t files

[Kit Hannah]

I have a question for all of the Vegas /FS-4HD /JVC HD110 users out there.

I was reading a few posts that mentioned the problem with audio / video drops (a couple of frames) between segments. Many suggested that this is not a problem with the JVC HD-110's because of the back space setting, but I have the 110's with the FS-4 HD and Vegas 7, and it has gaps. It basically jumps between clips when recording .m2t files. I've done everything everyone has suggested in other posts. Still has gaps.

So, my question is, has anybody found the work around for this problem, or have newer versions of Vegas taken care of things? The cameras are a week old and the firestore drives came in yesterday morning (3 of them drop shipped from Focus Enhancements). They all have the latest firmware.

I'm somewhat disappointed at this point. If we can't output to HD on the Firestore's (we're not going to capture 40 + hours of tape for each of our projects), what was the point in spending all this damn money to "upgrade" from our DV5000's? To me, it seems like we've almost downgraded now because we have 1/3" SD chips instead of 1/2 ".

Ideas anyone?

[Christian de Godzinsky]

Hi,

I am not sure if you are referring to the following problem that IS recognized by Sony, but not yet fixed in 7.0d:

The automatic scene detection (importing m2t files directly from the cam wia firewire) does not work. The audio is missing at the end of every clip (for a couple of frames), additionally the last frame in one clip might belong to the next clip. The only workaround is to disable the automatic HDV scene detection and do it manually. Might your problem be related to this?

regards,

Christian

[Bill Ravens]

not sure what you're workflow is, but, my processes is working seamlessly.
1-capture m2t on FS4HD.
2-plug into cmputer and copy m2t files to raid 0 hard drive
3-transcode m2t files to CFHD with HDLINK
4-put CFHD on timeline, sequentially by timecode
5-edit and render

no skips, no pauses, no dropouts

[Kit Hannah]

My workflow is the same as yours Bill, although I don't dump it to the Cineform Codec.

JVC HD110's > Firestore Fs-4 HD / .m2t > Vegas

We are not capturing with the computer, rather taking clips straight from the Firestore.

I have seen where some people said they are dropping audio at the end. Mine is actually droping entire frames between clips, maybe 2-3. I thought this might have something to do with the clip ending in the middle of the GOP, but not sure what to do at this point. It just jumps ahead, like the 3 frames are missing.you'll see a noticeable little "skip" where each files lines up to the next.

When you guys put 2 continuous .m2t files on the timeline, does it do the same thing at the splice? I may have to go the cineform route...

[Bill Ravens]

While I've never experienced a gap in joined CFHD files, there's some odd things happening when I do a transcode from m2t to CFHD.
1-I ALWAYS seem to get an extraneous clip with 0Mb size that contains nothing( I always turn off scene detection).
2-sometimes, if I try to batch convert a series of m2t clips, HDLINK fails. The workaround is to convert each clip one at a time. Cumbersome, but, it solves the prolem.

It seems, to me, that there are things happening in the JVC workflow that no one has, as yet, owned up to. Whether it's JVC, Firestore, Cineform, or Sony, I don't know, but, there's something not right.

[Kit Hannah]

Thanks Bill.
What I will do then is see if premiere pro does the same thing. I get the 0kb file too on the Firestore, usually a few of them. Cineform may be the way to go, but I honestly did not think that it was going to be this much of a hassle with the HDV stuff. We used to run DR-5000's on the back of our DV5000 cameras, and I could not have asked for an easier workflow - drop it in, edit, render and transcode - everything looked flawless. I will post what my findings are, but if you or anyone else hears anything, let me know. Something definately needs to be done about all of this because it is simply unacceptable.

[Bill Ravens]

Good luck with PPro. A search of this forum will bring up TONS of problems with a 4 sec dropout, mostly with FCP users, and I beleive the same issue is happening with PPro.

I think, fundamentally, this is very much like the early days of DV. Ultimately, all these kinks are gonna get worked out, but, it's still early in the development stages of HDV. Given the poor communication in this business, it's a wonder any video standards get defined, at all. Guess I shouldn't complain....it took Microsoft to bring some level of standardization to desktop computing.

[Matti Remonen]

Hi,
this is indeed something that has been discussed here in the past. I myself and Christian here did swap some emails concerning the issue a while ago.

I did some testing with different capture apps and methods. The pictures below are actual snapshots from Vegas 7c timeline. The Video tracks are named (Audio follows the video):
- Cineform m2t -> uninterrupted m2t-stream captured with HDLink/ConnectHD
- Sony m2t -> m2t-stream captured with Vegas VidCap; scene detection on
- HDVSplit m2t -> m2t-stream captured with HDVSplit; scene detection on
- Cineform AVI -> captured with HDLink/ConnectHD; scene detection on; converted to CFHD on the fly

And the images should contain following:
VegasHDV_1.jpg shows how the audioin CFHD is lagging approx. 1.5 frames when compared to m2t-streams (regardless of capture app)

VegasHDV_2.jpg:same thing but zoomed so that you can see the frame numbers. Also if you play all audio tracks simultaneously, you can hear the echo, which will go away if you mute the CFHD-audio stream. So the problem is not just related how Vegas shows the "audio graphics"

VegasHDV_3.jpg: Here you can see how material captured and splitted by HDLink is shorter than the two others (HDSplit & Vegas). So it handles scene detection differently. Sony VidCap is bleeding to another scene...

VegasHDV_4.jpg: Here you can see the muting of the sound just before clip ends. As you can see from the upmost track the audio continues without any change in volume. HDVSplit seems to be a tad better than Sony VidCap. Clips start from the same position.

VegasHDV_5.jpg: And here's the last evidence: Sony VidCap "bleeds" to next scene altogether. HDLink has so big "safe margin" that it is not shown at all.

And I agree with Bill, we are in very early stages of HD(V) and the problems are related to that.

[Kit Hannah]

Thanks for that, but I am not capturing anything, nor am I converting anything yet.. We're using a firestore, which is supposed to be "seemless".

I'm wondering who out there is successfully using the firestore to semlessly drop .m2t files onto the timeline without having gaps in between the frames. This may in fact not be a vegas problem, but more of a Focus Enhancements problem. I'm wondering if I'm doing something wrong.

Bill Ravens is the only one that has come forward thus far and said the workflow is working for him. But I believe he is using a different camera than we are, so that may be some of the problem.


Bill, Here's another question for you. When you are recording to the firestore, what do you have it set to for your record settings, other than the .mt2? Are you using the Syncro function, tapless, etc? We recorded with the "tapless" setting and this is where we are at.

All I am saying is that for the people this IS in fact working for, what are you doing differently than I am? If it is working properly for them, I want to do what they are doing so I don't have to sync everything 120 times.

I would really appreciate it if some people could post what settings they are using on the firestore to make this work, what settings you are using in Vegas, etc.

Thanks

[Matti Remonen]

Thanks for that, but I am not capturing anything, nor am I converting anything yet.. We're using a firestore, which is supposed to be "seemless".

OK, sorry. Not familiar about the camera in question, therefore I thought that you were first recording to a tape.

[Mark Goldberg]

Originally Posted by Christian de Godzinsky

Hi,

... in 7.0d:

The automatic scene detection (importing m2t files directly from the cam wia firewire) does not work. The audio is missing at the end of every clip (for a couple of frames), additionally the last frame in one clip might belong to the next clip.

That is exactly what I have noticed in all versions of Vegas 7. That last frame or two is something that has to be dealt with in editing.

However, I am not ready to give up scene detection. I do lots of editing anyway, and I have added a workflow item to clean this up. Having to manually pull apart the scenes would be much more work.

[Bill Ravens]

I'm setting "Tapeless", and "Syncro". but, I've also shot with tape and syncro mode. Since my unit is an older FS4 that I updated to HD with the purchase of a firmware upgrade, I don't have an option to set the timecode mode...it sets only one default. I think that's the only choices I have. Let me say that I've never looked at my timeline for 1-2 frame interruptions in the timecode. I do, however, shoot a lot of 1-2 hour live music performances. After the workflow I've described above, I have never seen or heard an audio dropout or jump in the video. I suppose I would notice a missing frame or two.

I'll also add that when I look at the file structure that is created by the FS4 when I format the hard drive, it creates 10 directory folders number 0 to 9. These folders are always empty and the recorded m2t files are put in a seperate folder. I've never figured out why those other folders are there.

One more question to you...are you converting in HDLink or within Vegas 7? Cineform claims the two codecs are identical, but, I wonder if there's a difference. BTW, within HDLink preferences, I always set the longer render switch.

[Kit Hannah]

At this point, I have tried almost everything. From converting, different programs, etc. Womble didn't look like there was a jump, but it did get sluggish around the transitions. I think I am going to give Newtek's new Speededit a try - it looks pretty intuitive, but first, I'm going to step up to a duo core processor with a bunch of ram (4-8GB) and see what that does for me. I am also going to make it a clean install, not connected to the internet, No BS programs, etc. so I don't have to run anything but my NLE. I will keep playing with it, and when I find something that works (or I should say "if"), I will let everyone know.

[Kit Hannah]

I really just want to get to the bottom of all of this, narrow it down to know if it's a Firestore issue or something with the different NLE's. If it is a Firestore issue, and their HD is not compatible with any NLE for smoothness between clips, then I will be having a chat with them.

Bill, if you have some time, could you do me a favor? Can you take 2 consecutive native .m2t clips, drop them together on your timeline, and see what in fact happens for you? Scroll over frame by frame the splice and see if there is a jump....but only if you have time. I may post in some other forums later to see if people with other NLE's are having the same problem.

[Jason Robinson]

Originally Posted by Mark Goldberg

That is exactly what I have noticed in all versions of Vegas 7. That last frame or two is something that has to be dealt with in editing.

However, I am not ready to give up scene detection. I do lots of editing anyway, and I have added a workflow item to clean this up. Having to manually pull apart the scenes would be much more work.

Unfortunately for me, I still work with Vegas6 so I don't have scene detection for my HD capture.

jason