AC3 problems - how to edit m2v/AC3 combo?

[Wender]

Hi,

When demuxing a VOB set for editing (to create fades etc) and then for sending it off to DVD Studio Pro - I have encountered a problem: Final Cut Express does NOT handle AC3. I read somewhere it had to be transcoded to AIFF or something else but I don't want to do that, since transcoding and then reencoding it reduces quality.

I'm using MPEG Streamclip to cut the VOBs and then demuxing them. The resulting files can be sent straight to DVDSP for authoring, but when I want to do some simple edits before doing that - then what??

Any help? Thanks.

[terryj]

Don't transcode them, instead record them to new
files using Wiretap or Audio Hijack Pro.

Play the vob set using VLC,
and record the sound that plays using one of the above mentioned apps to 48khz AIFF 16bit.

And thus you have a NEW file, not
a transcoded one, that you can match up and edit.

[Wender]

Erm. Nope. Using those apps would be the same as a transcode. That's real-time re-recording and the format is AIFF or similar. What I want to do is to PRESERVE the VOB or m2v/AC3 combo. If I can't do anything else than clip them using MPEG Streamclip and then use those files in DVDSP then so be it.

[terryj]

so be it then.

What did you expect from a finalized format?
*shrugs*

Vob= the end result.
without either :

(a). going back to a source file to re-edit
(b). Transcode the end result VOB into a workable format
( its elementary streams) to edit/manipulate
or
(c) re-create the part you want to edit, which in your case is
actually going to be not a minor task but A MAJOR TASK
(All audio starts as AIFF, then becomes transcoded to AC3,
which is a non editable final file), either through real time recording /hijacking/wiretapping
( Paul from AHP Help Forum states:
"However, when you record the hijacking, you're getting
the AC3 stream decoded to AIFF, and then recorded back into AIFF or even MP3. [sic]")
or if you are EXTREMELY luck, can get a GOOD copy
from some alternate source, which you HOPEFULLY can
sync back with your .m2v.

lesson here, keep your source files until your sure
your happy with the finished product.

[Wender]

Okay. Thanks. I think you misunderstood. My source files are VOBs - recorded from TV on a Pioneer DVR-630. Unfortunately not in LPCM mode which I use now but in XP which uses AC3 audio.

So that's the source, OK? I can use MPEG Streamclip to cut the VOBs directly, and save the cropped/trimmed VOBs again. Easy. Then I can DEMUX those VOBs to m2v and AC3 and use those files directly in DVDSP. Still no transcoding. End result is a nice DVD with no degradation of quality, no transcoding.

BUT: The problem arises when I want to i.e. create a fade in or out to parts of the video. Can't be done in DVDSP or in MPEG Streamclip so I was hoping for FCP to be able to handle it. Nope. That's the qhole reason for posting this question.

Conclusion: No fades. Just cuts. Nice DVD nonetheless and no transcoding done. Agreed?

[videopoo]

MPEG video consist of I frames which are spaced at intervals in the stream. these are the only frames that are editable. you cant do want you want without transcoding (ie; fades)

[terryj]

yes, videopoo that is correct.
http://www.pctechguide.com/24digvid_MPEG.htm
among others...

and Wender, I understood u correctly.
You didn't get what I was saying.
You need editable file types for FCP, such as QT MOV or DV.
m2v and ac3 are neither, as you have found out
trying to ingest into FCP and FCP says " neener, neener".


If you don't have editable file types
( in your case, you don't)
your only option is to create some.

Doesn't your home recorder have FW out?
if so, it would have been easier to send the
video direct to the Mac...Since I have a Canopus
ADVC-100, I would have just used the RGB ports
on your Pioneer to correct direct to my Canopus,
and then in via FW to my mac.....

http://www.avland.co.uk/pioneer/dvr630/dvr630.htm

that would then be pure DV in, and EASILY editable in FCP.