Interesting enough, I'm going to be talking transcoding in my FFmpeg talk at PLUG West next week :D
Basically, you'll have to play with some of the coding options. Here's a snippet from my own makedvd script. I used to use it to transcode avi files to create the mpg2 file would get authored into a proper DVD:
~ ~ ~
if [[ $3 == "quick" || ! $3 ]]; then
echo "converting $1 to $2 (quick mode)..."
time ffmpeg -y -i $1 -target ntsc-dvd -ab 224k $aspect -sameq $2
if [[ $3 == "best" ]]; then
echo "converting $1 to $2 (best mode)..."
time ffmpeg -y -i $1 -target ntsc-dvd -ab 224k $aspect -bf 2 -mbd 2 -sameq $2
if [[ $3 == "tight" ]]; then
echo "converting $1 to $2 (tight- smaller GOPs for better a/v sync)..."
time ffmpeg -y -i $1 -target ntsc-dvd -g 12 -ab 224k $aspect -bf 2 -mbd 2 -sameq $2
~ ~ ~
This ffmpeg string is pretty dated but I suspect might still work. The things of note are "-sameq" which yields the "same quality" as the source. From there, the place where you'll have the most flexibility is audio bit rate. 224k is pretty high and accommodates 5-ch audio well but if you only have 2-ch audio (stereo) you can drop that 192 or 128. Note that, this assumes that the dumped mpg2 (vob) file already contain the video and audio tracks you want.
From a single video and audio track on single layer media over 2 hours is pushing it but you might be able to do it. At a certain point, because of DVD specs, you're going to have to sacrifice resolution or video bit rate.
-bf is for B-frames
-g is for your GOP size (default is I think 300. I'm used to use 12 here for really a/v sync issue so if you have a good source, you could make that number higher to make the file smaller)
As I said, I haven't used this in a very long time since my last DVD players could play avi, mp4 and mkv file but hopefully this will help you get started in finding the right combination of parameters that will work for you.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
Keith C. Perry, MS E.E.
From: "john boris" <firstname.lastname@example.org>
To: "Philadelphia Linux User's Group Discussion List" <email@example.com>
Sent: Monday, December 14, 2015 11:24:58 AM
Subject: [PLUG] Looking for dvd shrink software
I was pointed to a piece of software that would reduce the size of a video so it would fit on a dvd without losing resolution. I was told it was dvdshrink. I did a search for it and found a site but it sets off all kinds of alarms on my machine. Has anyone on the list used such software? I have a video that is about 2 hrs 40 minutes long and I am trying to get it to a dvd without going to a double layer disk. I want it to be playable on most DVD players.
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