[FFmpeg-user] novice, in need of advice regarding format conversion

Ronald F. Guilmette rfg at tristatelogic.com
Tue Jul 17 22:30:06 CEST 2012

In message <20120717080949.GE9329 at arborea>, 
Stefano Sabatini <stefasab at gmail.com> wrote:

>On date Monday 2012-07-16 16:27:49 -0700, Ronald F. Guilmette encoded:
>> Given that I don't really care if I have to leave my main machine crunching
>> all night just to convert (with maximum quality) each one of my input DVDs,
>> I need to know:
>>    1)  To which of the BD670-supported formats (USB/DLNA) should I convert
>>        my DVDs?
>Do ffmpeg -codecs and ffmpeg -formats for getting an idea of the
>formats supported by ffmpeg, also keep in mind the difference between
>the audio/video elementary stream format, which is encoded/decoded by
>a CODEC, and the container format, which usually corresponds to the
>file suffix.

Thanks.  That's probably the only thing about all of this stuff that I
_did_ actually already understand.

>If you want something pretty portable, i suggest MPEG2 or MPEG4 part 2
>(which is the equivalent of "divx") or H.264 for video, MP3 or AAC for
>audio, AVI, MP4 or MKV for the container (format) should be fine (mkv
>is less "portable" - meaning that some players may not support it, but
>definitively nice for the supported features).
>The lowest common denominator for players will be the
>mpeg2video+MP3+avi combination.

As I said, I only have one target here, i.e. _anything_ that the LG BD670
can play (and I don't care which container/codec are used, as long as the
LG BD670 is happy).  In short, I have -zero- reason to care about

Also, I think that for what I am doing, I will want to use whatever format
gives me the MOST quality and/or functionality... NOT the ``lowest common

Lastly, as my prior popsting mentioned, this player allegedly supports .MKV
files.  If that container format provides more functionality that the other
supported container formats, then that is probably the one I want to convert
my .VOB files into.  Now I just need someone to show me precisely how to do
that.  (An example command line please!)
>>    2)  What are all of the ffmpeg command line options I should use for each
>>        conversion?  (Perhaps it goes without saying, but I would like the
>>        quality of the output video+audio to be as good as, or nearly as good
>>        as what is on the original DVDs.)
>Example command:
>ffmpeg -i INPUT -vcodec mpeg2video -acodec libmp3lame out.avi

Someone else already responded to me privately and pointed out to me that
my pre-existing .VOB files are _already_ MPEG2 files... just with a funny
suffix.  On this person's advice, I tried copying one of my input .VOB files
to a file with the same name but with a .mpeg suffix, and then tried playing
that on the LGBD670.  That worked just fine, both video & audio, *however*
for reasons that perhaps someone somewhere could explain to me (please?)
the player refused to allow me gto use either the remote controls fast-
forward button or its fast-reverse button when playing this ``converted''
(but really just copied from .vob) .mpeg file.  (That is not really an
acceptable outcome as far as I am concerned.)

So anyway, I'm a bit confused because the command line you suggested above
seems to be one which would convert my input (.vob aka MPEG2) files to....
MPEG2.  No?  If so, that ``conversion'' does seem rather pointless, does it

>then start tweaking from it.

Hummm... I guess that I should have been a bit more clear in my prior
posting.  Allow me to correct that oversight now.

I do not know squat about ffmpeg, nor about its gazillion options, nor about
video/audio file formats and codecs generally.  so telling me to ``start
tweaking'' is sort of like telling a blind man to pitch a no hitter against
the New York Yankees.  I need some help & advice on the best options to use.

>> Help in the form of suggested ffmpeg command lines would be much appreciated
>More than this, I suggest to give a read to the manual page or other
>resources on the Internet, I don't feel like I want to rewrite the
>manual here.


% man ffmpeg | wc
    4738   20613  177135

Yea.  *Just* the man page is nealy 5,000 lines!

I don't know how anybody might expect a novice, who doesn't even understand
most of the terminology, to read over that WHOLE thing, just to try to
accomplish what seems like it ought to be a relatively simple task.

One last word... I did manage to convert (using a simple command line involving
the -sameq option) one of my test .vob files into a .mp4 file, and that plays
just fine on my LG BD670.  And unlike when I just copied the .vob file to
file with suffixes of .mpg and/or .mpeg, in this case I _could_ use the
fast-forward and fast-reverse controls on the LG BD670 remote control to
cause the thing to fast-foward and fast-backward through the .mp4 file.
That is the good news.  The bad news is that the .mp4 file was about 1.7
times the size of the original .vob file!  Why?  What gives?  I really
don't understand this.  Isn't MPEG4 supposed to be *more* space efficient
than the earlier MPEG2?

Anyway, I still am looking for help here, and I would still like somebody
to give me a good (or best) ffmpeg command line.  I also tried using ffmpeg
to convert to a .mkv file, but I must have screwed that up somehow, because
the player refused to play the resulting .mkv file, even though it allegedly
supports .mkv format.


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