[MEncoder-users] Encoding iPhone MOV into MPEG-2 -- Video framerate is super fast!?

[L Lee]

On 11/10/09 11:06 PM, "Jarred Nicholls" <jarred.nicholls at gmail.com> wrote:

> Wow that actually is working!  I used -mc 0 and figured since that didn't
> work there was no hope.  LIterally -mc 0.1 is the only thing changed and now
> all of a sudden it's fine.  How does that help the situation when mencoder
> (and ffmpeg actually) doesn't correctly identify the source's variable
> framerate?

Don't' look a gift frame in the pixel. I can say that because I'm in Texas.
(In other words, I don't know.)

> 
> So yeah, after using -mc 0.1, it is no longer showing the same problems as
> before...however, the audio is slightly behind the video.  Between 500ms and
> 1sec I'd say.  I did something funky as a workaround, but not sure if it
> will be a universal workaround.  It did work surprisingly well however:  I
> used ffmpeg to copy the MOV's audio and video and mux it into an AVI
> container verbatim.  I then used the same exactly mencoder command with "-mc
> 0" added to it, and the resulting MPEG-2 was spot on.  I'd prefer to make
> mencoder work in one shot, so is there anything else I can do to help the
> a/v sync after adding "-mc 0.1"?  Maybe -nobps?

Are you using Mac OS X (I wondered because of the format of your command
line)? If so I can send you an Automator workflow to let you apply an
offset, which you specify when the workflow is run, to an mpg file with ac3
audio. I can also send you an AppleScript droplet that employs the
ffmpeg/sox workflow mentioned a few weeks ago on this list to brighten the
tempo of an ac3 file using a factor based on an amount that you enter in
milliseconds when you drop the ac3 file on the droplet's icon.

> 
> I'm not cropping but I do need to scale to bring the "rotated" height down
> to 480 to fit onto a 720x480 stage.  That is NTSC DVD compliance and my
> optimal output.


The crop values I provided preserve aspect ratio while cropping enough
(leaving wide enough pillar bars) to preserve most of the original frame. I
would prefer to take a 4x3 chunk out of the vertical middle of the video and
make it big enough to fill a standard DVD frame. Here's an example that
keeps aspect ratio mostly intact but slides the frame above center enough to
keep most of your subject in the frame. It's sort of a vertical pan and
scan. Replace your "expand " filter with "crop=480:360:0:96,scale=720:480".

Laine Lee