[MEncoder-users] subtitles expand problem

[Phil Oleynik]

jsuzuki at free.fr wrote:

>Sorry, I sent the following messages to the mplayer list, but here is more
>appropriate:
>
>---
>>From a DVD to a divx using the latest mencoder, I achieved placing the subtitles
>in a black region below the picture using the -vf expand and -subalign 2
>options.
>The only problem is that subtitles "stick": that is the previous subtitle is not
>erased when the new one comes up, which is especiallay annoying when a 2 line
>subtitle is followed by a 1 line one.
>Is there an option I forgot?
>Thank you very much for your help,
>---
>* JustFillBug replied:
>Yes, I had the same problem. Apparently with -vf expand=xxx:xxx::0
>instead of expand=xxx:xxx:::1 fixed the problem. The setting seems
>against the manpage but what do I know?
>---
>* to which I replied:
>I found a way to make it work using the undocumented -nooverlapsub and
>expand=xxx:xxx::0 but without cropping or scaling the movie.
>If cropping qnd scaling is involved, it fails in both cases. My relevant options
>are:
>
>-vf crop=704:544:8:16,scale,expand=0:-50:0:0:1 -zoom -xy 640 -nooverlapsub
>-spualign 2
>
>Anything I can do to help debug the problem (I'd really enjoy that feature)?
>
>John
>
>PS: I am looking at the code in vf_expand.c, as I suppose it is where the
>problem lies...
>
Hello!

First, I should notice that "-xy ###" usually works only with overlay 
while playing.
For software resize (if you are do not live-encoding aware) use this option.
-vf scale[=w:h[:interlaced[:chr_drop[:param[:param2[:presize]]]]]]
See docs for how it works, there is about a kilobyte of text, I cannot 
put it here...
You were advised to use scale, as I see, without params - it works when 
playing, but I doubt it works
on recoding.

"expand=0:-50:0:0:1" - it will add black stripe down, and that area may be not
cleared! Try to compress without black stripe. Maybe, it will look good. 
Do not forget about sub-bg-alpha option.

But my own advise - DO NOT hardsub movie, use matroska container 
(http://www.bunkus.org/videotools/mkvtoolnix/)if you REALLY need UTF-8 subtitles. 
Subs take a pretty large amount of bitrate, you will lose in size greatly. 
If you wish to add 7-bit subs, you may use OGM container 
(http://www.bunkus.org/videotools/ogmtools/)
Again, if resulting video is not for VHS recording - do not hardsub.

If nothing works - try at first reencode to chosen size, e.g. bitrate 3000, and
then encode with titles rendering

Good luck, Phil