m4v muxing

[Kurgan71]

Hi

I have an MKV file that I remux into a m4v container using Yamb (this is my first try, I'm preparing for my new Apple TV 2). The file contain a video, an audio and a subtitle part. When I play it in VLC the result looks fine but regardless what font size I use in Yamb the playout on iTunes and QT shows a subtitle with size ~72 (compared to word) and in the middle of the screen. Any idea how to change some metadata in the container to use another size or as an alternative change how iTunes and QT play subtitles with default settings.

I'm on windows 7.

[Kurgan71]

I've read up a bit and from what i gather it is actually MP4Box that add the subtitle track when Yamb is muxing. Is this correct? haven't found any configuration for MP4 either though...

[Kurgan71]

Found that if I extract each track from the MKV and convert srt to ttext before muxing the size is fine but the text is still vertically centered in iTunes/Quicktime and bottom aligned in VLC. Any ideas or suggestions of other tools that will re-mux MKV to m4v (without re-encoding)?

[Kurgan71]

Nevermind I think I solved it using mp4box gui instead. Looks good initially, gonna look further...

[guns1inger]

Unless the subs are actually converted to images during muxing, the actual position, font and size will be down to the player being used. Some players offer the user much more freedom to set these than others. iTunes/Quicktime are some of the most featureless players when it comes to user options. iTunes basically gives you subs as being either off, or a language. Players like VLC or The KM Player offer a much wider range of controls.

[Kurgan71]

Aha, I thought MP4BoxGUI output soft subs as well. Of course I want soft subs, then the issue is not solved

I understand your point that iTunes/QT are featureless and I agree. But there should be some way to hint a default position to the program where the subs should be placed during playout. I mean Apple obviously gets there own m4v files correct... And I also managed to change the font size iTunes playout by converting SRT to TTXT before muxing. So it can't be completely up to itunes in this case.

[guns1inger]

The TTXT subtitle format does support positioning information - http://gpac.sourceforge.net/doc_ttxt.php - and mp4box can produce TTXT format subs. The issue is working out how to get the position information into the subs correctly. While they are text files, the are xml based and fairly complicated, as opposed to SRT's very simple formatting. Quicktime pro is another alternative, if you take an SRT file and rename it with .TXT as the extension. Again, I have no idea how to get the position information correct. Obviously Apple have tools that allow them to create fully compliant xml based TTXT subs, but they don't seem to be sharing, and no-one seems to have written a free alternative.