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View Full Version : Has anyone achieved frame-accurate commercial cuts?



scarabus
04-09-2003, 12:11 AM
cos I still haven't. I'm currently using TyStudio to extract, Womble MPEG-VCR to edit and demux, and Maestro to burn, but the result lost sync and in places had dreadful flicker, as if the frame order was wrong.

Ho Hum.

Fugg
04-09-2003, 10:54 AM
I've been able to get frame accurate editing using mpeg2vcr, but I have to save each section I want to keep as a seperate file and join them together afterwards. ie. no cutting on the origional file, simply select the vid between the commercials and copy(save) to a seperate file. (mpeg2vcr ver 3.13)

It keeps sync that way, but the problem I have with doing it that way is that it creates a "Temporal Reference Error" at every cut point!

It looks great and keeps sync, but spruceup refuses to import it.
:mad:

Damfino
04-09-2003, 11:42 AM
Am I missing something? I can't find any options in MPEG-VCR (3.13) to do a cut without reencoding the original file, so I haven't played with it. Is there some option that I can't find?

I'd like to be able to merge/cut without reencoding - sort of like TMPGEnc can do under "MPEG Tools", except that it crashes when I try to work with mpeg2 files...

captain_video
04-09-2003, 12:40 PM
Fugg,

I believe you're getting the temporal reference errors because you're notting cutting on an I-frame or GOP header. SpruceUp is intolerant of gaps between GOPs and cutting the video at any point is pretty much guaranteed to give you the fault you're seeing.

How are you able to merge the video segments together and how well does it work? I want to try merging a couple of video segments from two different recordings but I'm not quite sure what's the best method to use. Perhaps you could post the process you're using.

Pr.Sinister
04-09-2003, 02:19 PM
Originally posted by captain_video
Fugg,

I believe you're getting the temporal reference errors because you're notting cutting on an I-frame or GOP header. SpruceUp is intolerant of gaps between GOPs and cutting the video at any point is pretty much guaranteed to give you the fault you're seeing.

How are you able to merge the video segments together and how well does it work? I want to try merging a couple of video segments from two different recordings but I'm not quite sure what's the best method to use. Perhaps you could post the process you're using.

I find that the method that is almost sure fire to merge with
perfect sync is the Merge & Cut from TMPGEnc...

-Pr.

Fugg
04-09-2003, 02:54 PM
"I believe you're getting the temporal reference errors because you're not() cutting on an I-frame or GOP header."

Exactly. Mpeg2vcr does not "close" the gop frames when it cuts it in the middle. (I think!;)) Now if I could find something to "close out" the open frames before merging, we'd be in business.

"How are you able to merge the video segments together and how well does it work?"

as Pr.Sinister says, tmpgenc's "merge and cut" under "mpeg tools". Works like a champ!

"Am I missing something? I can't find any options in MPEG-VCR (3.13) to do a cut without reencoding the original file"

Select the segment you want and then click on the copy button and it will prompt you for a filename and to set the file properties. The default properties are set from the input mpeg, so if you don't change them, it does not re-encode.

Gateway
04-09-2003, 07:22 PM
well I have been doing editing for a long long time and really havnt found anything good for mpeg2 editing that does a good job plus if your cutting our commercials from a show, keeps the audio in sync.

with tystudio, i get a gop cut error, cant find valid cut point, BUT it does write out my mpeg file with all my cuts, odd, how ever its got a major audio drift so after 15 min the audio gets out of sync +/- 500ms or more :/

mini__me
04-09-2003, 08:05 PM
I use mfs_ftp to extract a ty, tyedit to convert easily to an SVCD compatible mpg, then bung it through M2-Edit to cut out ads, and demux and remux resultant M2-Edit mpg with TMPGEnc (M2-Edit mpgs seem to contain a load of extra unnecessary data)

M2-Edit works great for frame perfect editing, as far as I can tell :)

Gateway
04-09-2003, 08:25 PM
yep, it takes some jumping though some hoops to just freaking cut out commercials and try to get a working mpeg2 stream :/

Damfino
04-09-2003, 09:19 PM
"Am I missing something? I can't find any options in MPEG-VCR (3.13) to do a cut without reencoding the original file"

Select the segment you want and then click on the copy button and it will prompt you for a filename and to set the file properties. The default properties are set from the input mpeg, so if you don't change them, it does not re-encode.
Hmm... it doesn't work that way for me. If I hit copy, it just puts it on the "video clipboard"... hitting the save button makes it want to re-encode - it starts as a 112meg file, it wants to save it to a 520meg file! Ugh!

laserfan
04-10-2003, 08:08 AM
If you cut in the middle of a GOP, then that GOP has to be re-generated somehow (re-encoded) with a new I-frame, so any MPEG2 frame-accurate cutting is always going to require re-encoding as well. Right?

Pr.Sinister
04-10-2003, 09:34 AM
Originally posted by Damfino
Hmm... it doesn't work that way for me. If I hit copy, it just puts it on the "video clipboard"... hitting the save button makes it want to re-encode - it starts as a 112meg file, it wants to save it to a 520meg file! Ugh!

That's what it says but when you check the actual size on disk,
it'll be real small. Try it.

-Pr.

scarabus
04-10-2003, 02:53 PM
The problem with mpeg-vcr (and m2edit) is that they look at the stated bitrate of the clip and use that when doing any encoding.

You have to patch the MPEG first so that the bitrate is something reasonable. By default it's something stupid like 15M, so patch it to 3.5M

Then when you do a cut it will transcode the GOPs that are affected and leave the rest alone. But if you didn't set the bitrate the new GOPs will use very high bitrates and may not be compliant with DVD.

Its size estimates are based on the video length assuming CBR, so the files end up smaller than it predicts.

But sync gets lost in the process.

Gateway
04-10-2003, 04:36 PM
Has anyone figured out how to get tystudio to cut get the cuts right and no GOP cut errors?

also something I used to do along time ago that allowed me to cut out commercials and keep the audio sync, was to save each segment as a sperate mpeg file..

so if you have 15 min of the first part of your program, cut that save it, then do the next part after the commercials.. granted you can get like 3-4 segments for a 1/2 show..

crashmore
04-11-2003, 10:09 PM
I've been using a program called My Flix XE which does frame acurate cuts no problem without loosing synch. I've produced 20+ dvd's with this cut method and it's been perfect every time.
The only downside is the progam isn't cheap. So far it's been worth the cash to me as it's very fast, easy to use and produces great results.

http://www.mediaware.com.au

scarabus
04-28-2003, 12:55 PM
Okay, I've *finally* got it to work.

The key - as people suggested - was to chop up the source into chunks. I used TyStudio to create the source file, patched the bitrate with DVDPatcher (otherwise Womble generates high bitrate spikes) and imported it into Womble MPEG-VCR.

Then I cut each segment and saved them individually. I demuxed each segment with TMPGenc, then concatenated the MPEG Audio and imported into Maestro.

One of the clips gave me a GOP error, so I had Womble transcode it and that fixed the problem.

I kept each video segment seperate because I was concerned that sync may get lost and I might have to pad or trim individual clips. As it turned out sync was slightly out (audio was early) but I was able to adjust that by moving the audio on the timeline, and once in sync it stayed in sync throughout.

A slight annoyance is that the show is ever so slightly truncated, but since (like so many TV stations) TechTV d!ck around with the end credits to make more time for commercials I guess I can live with it.

TIVOROCKS
04-28-2003, 11:51 PM
Captian gave me some help on this awhile back....

Basically in a nutshell I...

1. Import the m2v and m2a into SpruceUp
2. Set chapter points at the beginning and ends of commercials
3. Compile the Title Set in SpruceUp
4. Rip the new Title Set in Smartripper deselecting the chapters
that contain the commercials. My experience has been that
commercials are all the odd Chapter Points and the save video
are all of the even Chapter Points. So I select Chapters 1 and
all the evens. Chapter 1 is the default first chapter created
by SpruceUp and has to be kept or the resulting new m2v
won't import back into SpruceUp.
5. The resulting m2v/m2a is commercial free and audio has been
in sync 100% of the time.


SpruceUp is acurate to the second. But the same proceedure
can be used with Maestro which is frame acurate. In practice,
for me, SpruceUp worked just fine if you're careful in setting the chapter points. For me SpruceUp was just alot easier to use
than Maestro to get my desired output.

I recently got all three 2 hr. SCI-FI episodes of The Children on Dune mini series on one DVD-R and that was sweet.

scarabus
04-30-2003, 10:06 PM
That works OK, but you get annoying discontinuities on the chapter boundaries. What I want to do is to SEAMLESSLY remove the commercials - cutting during the FadeToBlack before and after each break. The end result is that you can't tell there was ever a commercial break.

TIVOROCKS
05-01-2003, 12:46 AM
Try the above with Maestro. Check this thread out...

http://www.dealdatabase.com/forum/showthread.php?s=&threadid=21735

Look for the attachment called "processing steps.doc.txt" in a post by captian_video

Tuuv
05-07-2003, 11:46 PM
"4. Rip the new Title Set in Smartripper deselecting the chapters
that contain the commercials. My experience has been that
commercials are all the odd Chapter Points and the save video
are all of the even Chapter Points. So I select Chapters 1 and
all the evens. Chapter 1 is the default first chapter created
by SpruceUp and has to be kept or the resulting new m2v
won't import back into SpruceUp.
5. The resulting m2v/m2a is commercial free and audio has been
in sync 100% of the time."

TIVOROCKS

4. I had a look at Smartripper for the first time tonight and after a little trial and error found that the audio and video need to be demuxed to separate files for one to be able to import back into Srpuce. For others having a first look at Smartripper this is under Stream Processing and you must make the demux selection for the audio and video separately.

5. This is where I run into a little trouble. No matter what I tried the demuxed audio file is created with the extension .m2p. The video file is demuxed with the extension .m2v, which is fine, but both files have different names (prefixes) and that in as far as I can see is a problem for importing into Spruce.

From what I can see and understand out of Spruce's processing it will import the video file with extension .m2v and after that is finished it will automatically import the audio file with the extension .m2a. This is where the problem lies since the demuxed audio file has a different name than the video one and thus is not imported automatically, and even if it had the same name the audio file has the wrong extension.

Is there a solution in either Smartripper or Spruce for this instead of having to open a command line to change the extension on the audio file to .m2a? Changing the name (prefix) on the files to the same name for both is accomplished easily enough using explorer.

Thanks in advance for any assistance.

TIVOROCKS
05-08-2003, 02:01 AM
Tuuv...

Smartripper always gives you a long prefix for your m2v and m2a (or m2p). I always just right click them and change it to something shorter for example:

seinfeld.m2v
seinfeld.m2p

It doesn't matter what the prefix is but SpruceUp wants them both to be the same. After that then change your m2p extention to m2a. Windows will give you an error message to the effect that if you change the extention the file may become unstable or something. Just ignore and click ok. SpruceUp should import them now without a problem.

Whenever you rip the chapters in Smartripper remember to always keep Chapter 1. If you don't then the resulting m2a and m2v won't import back into SpruceUp. That 1st chapter is usually trash but you can just set the target for your play button to chapter 2.

itopia
05-16-2003, 04:37 PM
Frame Accurate commercial cuts can be achieved with TMPGENC DVD Author. Menu function is basic but the cuts are flawless. Pull streams with Tytool or Mfs Streams. Load into Tystudio and DO NOT Cut just process to Elemental no transcoding. Patch header to 720x480 and open it up in TMPGENC DVD Author to make commercial edits and menus. So far it has worked every time for me. Best of luck.

Adamp44
05-17-2003, 01:57 PM
What application would you recommend if I wanted to create a commercial free SVCD?