[mythtv-users] Crop in Transcode?

Robert Current robert.current at gmail.com
Wed Apr 25 20:51:56 UTC 2007

How do I check a file to find out what the format is?  Is there a
command line for that?

Apparently ATSC can be a lot of formats
(http://en.wikipedia.org/wiki/ATSC), and I'm clearly picking up some
that are 4:3 and some that are 16:9, and I'd like to somehow check the
file before beginning to process it.

(more below)
On 4/25/07, Rod Smith <mythtv at rodsbooks.com> wrote:
> AFAIK, there's no way to do this from the MythTV GUI; however, it is possible
> when using command-line tools. Here's one that I use (note that this is one
> big long line; it's split for e-mail):
> mencoder -vf kerndeint,softskip,crop=720:360:0:60,scale=720:480,hard
> dup -ofps 30000/1001 -aspect 1.7777 -ovc lavc -lavcopts
> vcodec=mpeg2video:vrc_bu
> f_size=1835:vrc_maxrate=9600:vbitrate=${vbitrate}:keyint=18:turbo:trell:dc=10:au
> toaspect=1 -oac lavc -lavcopts acodec=ac3:abitrate=192 -of mpeg
> -o ${dest} ${src}

That's doing about what I want, with some tweaking, I'll have to grab
the input dimensions, to test for size before processing to see if
processing (crop) needs to be done, and what input size to feed the
command line.

> I doubt if the black letterboxing bars consume all THAT much disk space; they
> are just static solid black areas, which shouldn't take a lot of data to
> encode. You'll also necessarily lose some quality whenever you transcode. If
> disk space is an issue, I'd recommend either examining your recording options
> or buying more disk space.

Are there ways to set recording options for DVB devices to something
other than what the stream comes in as?

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