Opinions for Best Export for damaged files

Kami_1 wrote on 10/8/2016, 2:25 PM

(MEP 2016)

Before I could copy the day's videos to the computer, something went wrong when I put the SD card into the computer card reader (and tried to delete one file). The entire "database" of the card was wiped out.

I used Piriform's Recuva and got back maybe 20% of the files. Fortunately, this included all the one of that day (all others were already on the hard drive).

However, the files aren't quite right. Each one starts with the contents of one file and ends with the beginning of another. And the beginning of each object on the MEP timeline has a few frames of black. I decided to make a backup before editing, so if something goes wrong with using the "recovered" original mpgs, I'd have files which are more reliable to work with. I thought MEP's mxv format would be best but but when I exported to that, it was ALL black. This made me more nervous about the integrity of the "recovered" mpgs.

This brings me to my request for opinions. I've tried several of the formats to export. Uncompressed AVI, of course, is the best, but the files are HUGE! The others I tried are DV-AVI, plain AVI, wmv and mp4. To my surprise, the last two are as good as other other AVI's, maybe the mp4 is a tad better.

I'm guessing I should use the uncompressed AVI's, but I'd very much appreciate opinions on which format to use for the backup exports.

Thanks.

Comments

johnebaker wrote on 10/8/2016, 5:53 PM

Hi Kami

Personally I would not use uncompressed AVI as an export - apart from the massive increase in file size you are not gaining anything visually over a mxv or mp4 file.

A mxv file is not as compressed as a mp4 and does enable better preview when editing on the timeline.

The damage to the files has likely messed up the fle header information in each file, this contains details of the file type, length, framerate, resolution, codec, etc, so that what MEP thinks it is getting and what it actually gets are not the same or , or the frametable is incorrect/corrupt if they are mpg files,.

If the recovered files are mpg files, once you have loaded then into MEP try selecting all of them then right clicking one and select Create frametable (new) before exporting the video.

If they are mp4's then there are many mp4 fixers available on the Internet, however I have no experience of using any of them, so I cannot recommend which one to use.

HTH

John EB

Kami_1 wrote on 10/9/2016, 1:26 AM

Hi John,

Thanks for the reply and info. The files are mpg's.

The mxv exports are all black, literally. It was the first export I tried. I do see a visual difference with the uncompressed AVI's. Maybe that's not an advantage because what it shows more clearly is lots of noise on anything in the shade.

I created the frametable after reading this, although I already did a lot of cutting. I still can't export to mxv. I got the text label I added, but all black instead of any video.

I didn't realize that mp4's can be used for editing. Do they lose anything when re-exported, as mpg's do?

I know there's damage to the file headers, as all the lengths shown in Windows Explorer are way off. (Dates and times are accurate.) I'm guessing that the black frames at the beginning of each object on the time line (not on the original mpgs) is part of MEP's difficult reading these files?

Oh .... Is there a direct way to Reply without quoting?

Kami

johnebaker wrote on 10/9/2016, 3:52 AM

Hi Kami

. . . . I didn't realize that mp4's can be used for editing. Do they lose anything when re-exported, as mpg's do? . . . .

If the video on the timelineare mpg 1or 2 files and the project settings are the same resoluton , framerate etc and you are using the MainConcept codec then there is an option to use Smart Rendering in the export dialog settings.

This enables MEP to literally copy the required parts of the clips on the timeline, it only re-renders those parts of the timeline where an effect, transition, title etc are located.

For the majority of exports to the same resolution video where smart rendering cannot be used, I have not noticed any significant deterioration due to re-rendering.

. . . . Oh .... Is there a direct way to Reply without quoting? . . . .

Yes, use the Answer button just below your original post.

HTH

John EB

Kami_1 wrote on 10/9/2016, 11:58 AM

Hi John,

Thanks for your always good information.

I have the "Default" mpg-2 codec selected. I see an option for "Smart copy" but not Smart Rendering. Are they the same, similar but different? There's also an "HRD" option (no idea what this is).

(While looking for which codec I'm using, I found an option which might solve another issue I've been having. )

I didn't realize the Reply button is for the reply in focus. Thanks!

Kami

johnebaker wrote on 10/9/2016, 4:26 PM

Hi Kami

Smart render and Smart copy are the same thing.

HRD stands for Hypothetical Reference Decoder which is a virtual decoder checks the rendered video for compatibility with the video standard during the encoding process. This ensures that the rendered video is compatible with different playback devices, however it does slow down the encoding.

IMHO unless you are experiencing issues playing back on devices then you do not need to use it.

HTH

John EB

Kami_1 wrote on 10/9/2016, 10:53 PM

Thanks again, John. Does "rendering" refer specifically to creating a DVD, or to any export, mpg, mp4, wmv, etc.?

johnebaker wrote on 10/10/2016, 3:34 AM

Hi Kami

Rendering refers to the process of encoding the video to the desired format and applies to both exporting and disc cration.

DVD or BD burning involves many processes which are:

Render (encode) movie to intermediate video format
Render (encode) menu
Render (encode) chapter menu and convert movie intermediate format to VOB or M2TS file
Create DVD (BD) image
Create API project for the disc burning program and burn it to disc.

Steps 1 to 3 will be repeated for every movie in the project.

The burn dialog indicates which step is being done. If you burn a disc with no menu or chapters then steps 2 and 3 may be missed.

HTH

John EB

Kami_1 wrote on 10/10/2016, 10:51 AM

Thanks John!! Information much appreciated and very helpful.

Kami