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PostPosted: Sun May 09, 2010 12:11 am 
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Joined: Mon May 10, 2004 8:08 pm
Posts: 1891
Location: Adelaide, Australia
I have a JCV Everio hard disk camcorder that records in 16x9 format. However when I copy files from it to my myth box using the USB connection, mythtv and mplayer both play the files back as if they were recorded at 4:3 aspect ratio so everything looks squished skinny.

I understand that this is because there is an aspect ratio specified in the mpeg headers in the file which must be wrong. In my search for a tool that would fix the files without having to perform a lossy transcode, I initially found the windows tool DVDPatcher (
http://www.wincesoft.de/html/dvdpatcher.html). This does the job but typical of a windows program is a pain to use (if you want to do a number of files) and has no command line interface.

Then narrowing my search to linux tools, I found mpgtx which can fix the files if I tell it to "join" a single file with the aspect ratio override selection, but it doesnt to it in-place (it needs to create a new copy). I can live with that though.

My question is: Is there another tool that can do this that is already included in LinHES? If not, I guess I'll add mpgtx to the extra-testing repo.


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PostPosted: Wed May 12, 2010 6:22 am 
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Joined: Tue Sep 12, 2006 6:03 am
Posts: 210
Location: Roseville, MI
I have had this same problem. I have the JVC Everio also, and apparently it shots widescreen video using Anamorphic Widescreen mode (http://en.wikipedia.org/wiki/Anamorphic_widescreen). The camera shoots at 720x480 which is not the standard 16:9 ratio. This generates "rectangular" pixels. The TV compensates and stretches accordingly.

I first noticed this problem trying to upload some family videos to youtube to show the grandparents. The video gets "squished" and everyone looks a bit skinner.

Let me know if you come across anything.[/url]

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LinHES R8: FE/BE, FE (x2)


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 Post subject: Anamorphic
PostPosted: Wed May 12, 2010 11:45 am 
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Joined: Mon Dec 18, 2006 1:20 pm
Posts: 98
Location: Krakow, Poland, EU
Hi Greg,

Greg Frost wrote:
I understand that this is because there is an aspect ratio specified in the mpeg headers in the file which must be wrong.

Or perhaps aspect ratio specified in the mpeg headers is right, but mythtv and mplayer both play the files back without taking that information into account.

If your camcorder is 480p capable and VGA (640x480, i.e 4/3 ratio), sampling pixels are square. In order to make a 16/9 aspect ratio picture fit into such a grid, picture coming from the CCD sensor has to be shrinked horizontally on the record. When later played, aspect ratio specified in the headers tells the player to stretch back the picture (by the way, pixels become rectangular then). Should the player ignore the information, it would display the movie according to default square sampling (4/3 ratio). Then, everything looks squished skinny, just as it has been actually recorded. If your camcorder is 480p capable and wide VGA (854x480, i.e 16/9 ratio with square sampling pixels), all that I wrote is nonsense.

Are you sure that DVDPatcher makes no re-encode ? I had a look at the link you gave, but drop reading as I cannot in German.

I don't pretend that my comment helps to save you from this issue, just that the flaw might be different than the one you thought about at the beginning.

Regards.


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 Post subject:
PostPosted: Wed May 12, 2010 9:07 pm 
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Joined: Mon May 10, 2004 8:08 pm
Posts: 1891
Location: Adelaide, Australia
DVDPatcher is so fast, it cant be re-encoding it.

I have been able to fix my files without re-encoding with both DVDPatcher on Windows and with mpgtx on Linux.

mpgtx is not currently available through the LinHES repos though. So basically I was asking if there is an included tool that does it. If not, I will add mpgtx to LinHES (extra-testing).

I dont know if the pixels are square or rectangular, but I have establisted that there is an aspect ratio flag, and the JVC is setting it wrong.


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 Post subject:
PostPosted: Thu May 13, 2010 3:58 am 
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Joined: Mon May 10, 2004 8:08 pm
Posts: 1891
Location: Adelaide, Australia
I have added mpgtx to extra-testing.

If you are pointing at the testing repos, you can get it by doing:
Code:
pacman -S mpgtx


To losslessly convert you JVC Everio MOD files to 16:9 aspect ratio, use a command like this:
Code:
mpgtx -j jvc_everio_file.mod -A3 -o outputfile.mpg


If I attempt to join files with mpgtx, it just seg-faults. However I have found that if you just cat them together to form a contiguous file and then run a lossless mythtranscode over it, it seems to work fine:
Code:
cat file1 file2 file3 > concatenated_file.mpg
mythtranscode --mpeg2 --video --infile concatenated_file.mpg --outfile file_that_plays_nicely.mpg


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 Post subject:
PostPosted: Mon Nov 01, 2010 1:20 am 
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Joined: Mon Nov 01, 2010 1:14 am
Posts: 1
MOD file format is used by various digital camcorder models (JVC Everio, Panasonic and Canon) to save their videos. These MOD files are often accompanied with small .MOI files which contain the videos' time-stamp information. MOD format is simply a MPEG-2 formatted video file, and if you simply wish to view the files on your computer, it is reportedly safe to rename the extension from MOD to MPG or AVI.

If your MOD files were recorded in 4:3 format then just rename them to MPG. If they are 16:9 widescreen, then you could use Pavtube MOD File Converter to convert them.
http://bitetune.com/play-mod-files-mac/


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 Post subject:
PostPosted: Mon Nov 01, 2010 7:49 am 
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Joined: Tue Aug 15, 2006 11:14 am
Posts: 1290
Location: Orlando FL
I just found a simple way to solve this problem last night. there is a program called sdcopy http://zyvid.com/smf/index.php?action=d ... 0.0;id=153 here is some info on how to use it. http://forums.cnet.com/7723-7594_102-145687.html
It runs on windows and you need to extract it so that it can create the .ini file. It's a simple little program that just copies the file and changes the extension and the name plus a little check box to say that it is widescreen.

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