ffmpegX codes an empty file

[Silvia]

Hi,

after "successful" installation ffmpegX codes, but the file is empty.
Not knowing how to use it correctly, even ift it looks very simple, I would need some advice what to do, that my VOB file is converted into a DV file.

Thank you for your help

Duration: 00:00:01.4, start: 0.242044, bitrate: 2147483 kb/s

Stream #0.0: Audio: ac3, 48000 Hz, stereo, 256 kb/s
Stream #0.1: Video: mpeg2video, 720x576, 25.00 fps
Codec type mismatch for mapping #0.0 -> #0.0

[tomlee59]

"Codec mismatch" suggests that you should try clicking the "invert mapping" option in the audio tab.

[Case]

VOBs shouldn't need "inverted mapping", unless you convert each VOB from a DVD individually, then a few of the VOBs may show this behavior.

Perhaps you didn't join the VOBs to one file containing all of the DVD Title.

[Case]

Duration: 00:00:01.4

1.4 seconds of video. Do try to play this VOB in VLC, to see if you really want it converted. It seems too short to be of significance.

[Silvia]

Invert Mapping has worked. Thanks a lot. Great, happy to start with cutting in a while.

I will also try the other advice received, but I thought for iMovie small parts of the movie would be better, than one huge file.

But I lost the high quality by converting it the first time. What can I do to keep that alive, besides clicking "high Quality" in the options?

Thanks
Greetings

Silvia

[Silvia]

by the way, the part of the movie is 5 minutes long, not just 1.4 sec.

[tomlee59]

Quality is a function of several factors. Bitrate and framesize ("resolution") are two of the most important. If the low quality you are seeing is a loss of definition even in static scenes, then increasing resolution will help (if bitrate is also allowed to increase). If static scenes look fine, but moving ones do not, then increasing bitrate directly will help. Clicking "high quality" reduces the bitrate required to achieve this latter result, but takes longer to encode. If conversion speed is more important than final file size, then leaving "high quality" unchecked may be preferable.

[Silvia]

thanks. Makes sence. I will try that.

Greetings
Silvia

[Case]

For DV files, the resolution and bitrate are fixed to DV specific values. Changing those may produce an invalid file.
You may experience a visual lower quality in you editing app (iMovie - which version?), e.g. because of interlacing. To be sure, check on a tv.

[Silvia]

Hi,

thanks. hmm... the files are much tooooo big (we talk about some gig.) to deal with it in IMovie...
I have to think about a new way. What would you suggest: MOV files? Which resolution?
Somehow in the first tests (converting it to MOV) the quality is not the best, as well the movie get stuck while audio is going on with Bitrate 1265 and Resolution 640x 352.
But hey, the first tests with a short videopart also show 5 MB instead of 150 MB. So some things changed to a better way.
Do you have more experience now what to do? Which file type etc...?

Greetings and thanks
Silvia

[Silvia]

the version I have and will use is still the old one (the other one is not comp. with my G4): iMovie HD 6.0.3, still sufficient.

Greetings

[Case]

DV is the native file format for iMovie for SD material. If you would import a .mov or .mp4 file, then iMovie will convert it to DV (unless it is HD, then it would use AIC) to be able to work with it. So you might as well import a DV file, to keep the number of conversions to a minimum.

Yes, DV files are huge. You will need loads of hard drive space to work with video files that are more than a few minutes.

iMovie HD 6.0.3 is pretty good, in some regards better than later incarnations of iMovie.

[tomlee59]

To expand a bit on what Case is saying, DV is only very lightly compressed (for high quality, and ease of editing), which is why the files are extremely large. So, you edit DV with iMovie, but then create your final file in a different format (e.g., DVD's MPEG2), which uses more compression to reduce file size further (at the expense of quality).

If your editing consists of little more than cuts and splices, you may not need to operate on DV files (but you'll then need something other than iMovie to perform those operations). The rationale for iMovie's use of DV is to allow for many different types of editing (and perhaps many of them), each of which might degrade quality slightly. By starting with very high quality, DV allows for an excellent final result, despite the cumulative degradations along the way. Then, once you are all through editing, you can convert the result into the final delivery format. The precise path you take is the result of trading off file size, editing convenience, your labor, and quality. There is no universally correct answer, but now that you know what the tradeoffs are, you can better make a decision about how to proceed.