Dear Wamuggers
I send this to the list as it may help Rob Davies and his DVD query,
especially relating to reference to "Gumby". It has a function to cut
and edit such files I think. Try it anyway.
Regards
Reg
_______________________________
As sent to GMUG, UberMug and Maced lists:
I was ready to post a message for help yesterday but have solved the
problem myself, with some "intrepid" web research. Now I know what
"muxing" and "demuxing" is. "So what?" you may well ask. Well then sit
back and take note. A simple task I set out on took all afternoon!
Our little Sony still digital camera can save MPEG video images. They
take up heaps of space on the dreaded "memory stick" but I took some of
the dogs at the river then decided to email them to family. As each was
over 3 Mb I opened them in Quicktime Pro (6.5.1 in OS X 10.3.3) and
exported them as "modem" size. I ended up with about 65Kb movie with no
sound track.
Upon investigation I discovered that the camera saves the movies in
MPEG format as "muxed" files. That is, as far as I can ascertain,
judging from the web reference No.1 below, combines video and audio
tracks as one track. Quicktime Pro, and iMovie, cannot separate these
tracks. Indeed my iMovie (3.0.3 - somehow I've missed upgrading to V4)
separated the tracks into video and audio, but the audio track was
completely silent! Exporting the movie from QTP in various different
formats didn't solve the problem. Simply put, QTP told me there was no
audio file, even though it could run the movie with its live sound.
A Google search for "muxed" revealed the definition below (No. 1). A
further search gave a reference to Gumby software (Ref No. 3) which in
its reviewer's terms "may solve the problem - no promises". (It
actually seems to be very good software but I ended up deciding bbDEMUX
is best, for this specific task, especially considering the download
size).
Gumby downloaded Ok but the Instruction Manual pdf was incomplete and
didn't give detail about its MPEG Fixer which was needed for the
process. In fact it was simply a matter of "drag and drop" remembering
to check the "Demux" box. It was a bit slow to open windows but did
eventually provide 2 files, the video one tagged .m1v and the audio
being .mp2. These files wouldn't immediately open into any application
but after then loading Quicktime Pro and importing the files, both
opened. Strangely I was not able to "Select All" and then "Copy" them.
I planned simply to open the video file, select the sound file, copy it
then "Add" to the video. QTP would not do this, and neither would
iMovie. It simply didn't recognise the files so they couldn't be
imported.
I then went back and downloaded bbDEMUX and mpgtx after searching on
Versiontracker (http://www.versiontracker.com/). bbDEMUX is the
smallest download and demuxed the movie immediately, simply drag and
drop it. It also showed the files as Quicktime Pro files. Gumby didn't,
which may have been the reason why they didn't immediately open into
any application, although as I said, after opening the app the files
imported Ok.
mpgtx looks great with nice buttons and menus but wouldn't run on my
iBook, so it's a dud tonight!
So now, here's the final solution.
I was able to open the .m1v video file into QTP then needed to export
it as a QT .mov. When it was reopened in this format in QTP I could
select all and copy (just to test).
I then dragged the audio mp2 file into iTunes and set it to convert it
to mp3. Then I dragged it out of iTunes and then imported it to QTP. I
then exported it as a QT .mov file. Then I was able to open it again,
select all, copy and "Add" it to the video movie and then finally
export it all as a normal QT .mov file, adjusting quality and other
settings to reduce the size to between 64 Kb - 1Mb for emailing.
Importing these newly converted fimes into iMove seems to work too.
Hey, I wanted to do something else this afternoon, not set out on this
"little learning journey"! surely we don't need to do this every time
we make a short movie?
Have fun. Here are the web references and some details of the software.
I'd love to hear of a shortcut for all this. Surely there must be a
better way.
Regards
Reg
1
Great website for definitions:
http://www.afterdawn.com/glossary/terms/multiplexing.cfm
Multiplexing or muxing, when speaking of video and video editing, means
basically a process where separate parts of the video (or 'streams' as
they're called in video terminology) are joined together into one file.
Typical process of multiplexing is where we have MPEG-2 video file
(extension normally .m2v), an AC3 audio file and a subtitle file and we
want to combine into MPEG-2 system stream file in order to burn that
file to SuperVideoCD disc.
Opposite process is called as demultiplexing or demuxing.
2
http://sourceforge.net/projects/macbbdemux
64Kb
Based on the UNIX program of the same name, bbDEMUX separates MPEG and
DVD Video Object (VOB) files into their component streams, letting you
work with all video and audio tracks separately. All source code is
open and free.
3
http://gumby.misplacedmac.com/
2.7Mb
Gumby is a multipurpose application for manipulating, fixing and
converting files found on the
net. Over the years, many tools have appeared to handle such files,
unfortunately the majority
have been PC-based, thus leaving Mac users in the dust. Gumby tried to
rectify this situation by
providing roughly 20 programs into a single application.
Gumby is split up into 15 modules. Here is a brief description of each
function:
• VCD Jelly: Extracts an mpeg-1 film from a file.
• SVCD Jelly: Same thing as above but for Mpeg-2 files.
• SVCD Fixer: Fixes SVCD's so they work on some players.
• Binchunker: Converts a binary file (.bin) to an ISO.
• SFV Checker: Performs checksum verification on files.
• PS2 Patcher: Patches PS2 images (CD or DVD) for the Japanese swap
trick.
• PPF Patcher: Applies PPF patches to images.
• MPEG Cutter: Cuts or trims MPEG documents.
• Unrar Extractor: Extracts files from RAR documents.
• PAR Checker: Fixes RAR documents using parity files (PAR).
• PS2 PAL: Converts PAL PS2 games so they run on NTSC TV sets.
• GI to ISO: Converts Primo DVD images to standard ISO.
• S/VCD Builder: Creates VCD or SVCD images from mpeg documents.
• MPEG Fixer: Demuxes, Remuxes, Fixes and Repairs MPEG files.
• Batch Processor: Automates multiples functions to work with 1 click.
http://www.biermann.org/philipp/mpegcut/
480 Kb
Mpgtx is a mpeg editor. You are able to split mpegs in chunks by count,
megabytes or minutes,
join chunks to one file or demux a mpeg. Mpeg formats supported include
mpeg1, mpeg2, mp2, mp3.
Mpgtx GUI is a wrapper around the terminal based application.
Woofwoof
