[mythtv-users] Automatic converting HDTV to MPEG2

bha at att.net bha at att.net
Tue Dec 12 03:51:01 UTC 2006


I have a similar issue: I use mvpmc as a client to a myth v.20 backend. I have a number of 'lo-def' QAM stations (via hd5000) that result in excellent mpeg2 recordings that DO play on mvpmc (since these recordings, while recorded from a digital signal - and hence have excellent picture and no static -, but are not high def). My problem is these recordings have their audio encoded using AC3 (or was it AC2), which mvpmc can't handle. This results in the video playing fine, but no audio on mvpmc. Anybody have a script (and/or MythTV transcoding tweak) that could change these mpeg2 recordings to have mp3 audio (or some other audio format that mvpmc might handle)?

Thanks,
Dan


Date: Mon, 11 Dec 2006 12:18:40 -0500
From: Boleslaw Ciesielski <bolek-mythtv at curl.com>
Subject: Re: [mythtv-users] Automatic converting HDTV to MPEG2

On Sun, Dec 10, 2006 at 07:52:55PM -0500, Trampas wrote:
> The problem I have is I use a MediaMVP as a front end and the HDTV Mpeg2 is
> not supported. Thus I was trying to figure out how to transcode it to a DVD
> or SVCD format such that I could watch using mediaMVP. 

I use the following hacky script (which requires mencoder) to convert
HD videos so they can be displayed using the PVR-350 hw decoder. I am
pretty sure it should work for MediaMVP as well.

The script assumes that the input video has 16:9 aspect ratio and the
resulting file is 720x480 with the original video letterboxed to be
displayed on 4:3 TV.

Bolek


#!/bin/sh -x

INFILE=$1
OUTFILE=$2

if mencoder -o /dev/null $INFILE 2>/dev/null | egrep -q 'fps:(59|60)'; then
    # progressive
    OFPS="30000/1001"
    FPS="60"
    FILTER="tinterlace=4,scale=720:360:1,expand=:480"
else
    # interlaced
    OFPS="30000/1001"
    FPS=$OFPS
    FILTER="scale=720:360:1,expand=:480"
fi

mencoder -of mpeg -mpegopts format=mpeg2:vbitrate=4000 -oac lavc -ovc lavc 
-lavcopts 
vcodec=mpeg2video:vbitrate=4000:keyint=18:aspect=4/3:acodec=mp2:abitrate=256 -vf 
$FILTER -fps $FPS -ofps $OFPS -vc mpeg12 -o $OUTFILE $INFILE


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