[mythtv-users] 16:9 Zoom - Transcode profile?

Rod Smith mythtv at rodsbooks.com
Mon Nov 5 19:31:27 UTC 2007

On Sunday 04 November 2007 23:08:23 Randall Hopper wrote:
>      Has anyone cooked a transcode profile to chop the edges off a ATSC or
> NTSC signal so that what gets transcoded doesn't include all the dead
> space?

I've got a custom transcode script that does this, along with lots of other 
things. I've just uploaded the latest version to my Web site:


Type the script name, the name of the source file, and the name of the 
destination file. The script then prompts for various things, such as video 
bitrate, cropping options, how to handle the audio, etc. Note that this is a 
work in progress and some features don't function properly. (Converting audio 
to 5.1 format is completely foobared, for instance. Also, file length 
detection often fails, so specifying the bitrate directly rather than as a 
file size is advisable.) If you wanted to call this script from the MythTV 
interface, you could probably modify it to hard-code the options you want or 
you could write a wrapper script that passes options from a file using input 
redirection. Alternatively, you could examine the options that my script uses 
to do the cropping and write a simpler script that does the cropping with 
whatever other fixed options you like.

Note that if you want to use the transcoded file as if it were the original 
(call it from the MythTV recordings list), you'll need to rename the files 
after the job is done and then manually transcode it from MythTV with the 
lossless transcoding option.

Oh, you should also check the script and make at least one modification, to 
the tempFile variable; change it to someplace that makes sense on your 
system, or to /dev/null. Since your e-mail suggests you're in the US, the 
target video format should be OK for you, but if somebody in a PAL country 
tries to use this script, they'd do well to modify the output format options 
(-ofps) appropriately.

My script uses mencoder rather than the ffmpeg that MythTV seems to prefer for 
this sort of thing. Thus, you may need to install mencoder. ffmpeg does have 
options to crop, so if you prefer ffmpeg, you could write a script to do the 
job with it. Check the ffmpeg man page for details on its options.

Rod Smith

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