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Author Topic: Subtitle rendering  (Read 1943 times)

Matt

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Subtitle rendering
« on: July 08, 2011, 04:54:29 pm »

Currently we're using ffdshow to render most subtitles.  This is nice because it's easy and it works with madVR.  

It also has some downsides.  We don't have the ability to allow a user to choose multiple languages when they use sidecar subs.  We don't know if subs are available for some files so offer "on / off" even if it won't do anything.

One proposed solution is for JRiver to create a custom subtitle engine.

Rendering would have to support the custom madVR output method and also the standard Directshow delivery (for EVR, etc.).  This doesn't sound too hard.

The hard part is all the subtitle formats:

1) Subtitles exposed by LAV Source / Splitter using the standard text pin
2) Sidecar files like .sub, .idx, .ssa, and about 20 other formats
3) Embedded subtitles that don't have a text pin (possibly the time-overlay on some home videos, etc.)
4) DVD subpicture information, which is encrypted (not really a subtitle, but not supported by madVR otherwise)
5) Line 21 information (currently we use a Microsoft Line 21 decoder)

Is it worth the time to create a custom subtitle system?  Is there an easier solution?

Thanks for any advice.
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Matt Ashland, JRiver Media Center

mojave

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Re: Subtitle renderering
« Reply #1 on: July 08, 2011, 05:39:18 pm »

Until the last few weeks, I've always used DirctVobSub. According to this website the latest version was released 5/12/11. I don't know how it compares to ffdshow or if there are any downsides.
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SamuriHL

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Re: Subtitle rendering
« Reply #2 on: July 08, 2011, 08:36:21 pm »

Please for the love of God create a subtitle renderer!  If done right, it will be a HUGE draw.  Think about it...you could do extended VOB subs which are on HD DVD's.  No sub renderer does that today other than ArcSoft's.  This would be greatly appreciated by many of us.
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rjm

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Re: Subtitle rendering
« Reply #3 on: July 08, 2011, 09:57:24 pm »

I'd be cautious here.

I have a gazillion videos with subtitles and yet have used subtitles only once or twice in my life.

I'd base the decision on the size of your non-English language customer base.
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SamuriHL

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Re: Subtitle rendering
« Reply #4 on: July 08, 2011, 10:00:39 pm »

There are NUMEROUS discs with forced subs for non-english sections of movies.  Avatar has alien language subs, for example.  I think the new LOTR extended blu-rays have elvish subs.  Forced subs are more common than you might think.  Plus I know I watch a bunch of foreign martial arts films where I prefer the foreign audio track with english subs.  Think Crouching Tiger on that one.  In any case, I think subs are used by a lot more people than you think.
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jmone

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Re: Subtitle rendering
« Reply #5 on: July 08, 2011, 10:52:27 pm »

The hard part is all the subtitle formats:

1) Subtitles exposed by LAV Source / Splitter using the standard text pin
2) Sidecar files like .sub, .idx, .ssa, and about 20 other formats
3) Embedded subtitles that don't have a text pin (possibly the time-overlay on some home videos, etc.)
4) DVD subpicture information, which is encrypted (not really a subtitle, but not supported by madVR otherwise)
5) Line 21 information (currently we use a Microsoft Line 21 decoder)

Is it worth the time to create a custom subtitle system?  Is there an easier solution?

Thanks for any advice.

I agree this is the hard part!  You could start with getting the sub renderer designed and working with say subs from the Txt Pin and see how you go (but if it went into production the calls will start for all the various formats immediately as it would need to be an all or nothing commitment).

Reliable high quality Sub handing is a PITA and I know of no other group contemplating a fresh approach to it.

To me Sub Rendering is very important given their prevalence on contnet these days as forced subs over those "burnt" onto the video itself (eg Bourne, Avatar, LOTR, Distrct 9 etc etc). 

I also agree that any sub renderer that is created will need to work with any combination of filters (eg the other option to consider is to use FFDSHOW for now as a RAW post processing filter just for subs regardless of what video decoder and video renderer is used - eg I'm doing this in combination with LAVCUVID or I'd get no subs at all).
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JimH

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Re: Subtitle rendering
« Reply #6 on: July 09, 2011, 07:10:18 am »

I'd base the decision on the size of your non-English language customer base.
It's about half our customer base.
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TheLion

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Re: Subtitle rendering
« Reply #7 on: July 09, 2011, 11:50:31 am »

Currently we're using ffdshow to render most subtitles.  This is nice because it's easy and it works with madVR.  

It also has some downsides.  We don't have the ability to allow a user to choose multiple languages when they use sidecar subs.  We don't know if subs are available for some files so offer "on / off" even if it won't do anything.

One proposed solution is for JRiver to create a custom subtitle engine.

Rendering would have to support the custom madVR output method and also the standard Directshow delivery (for EVR, etc.).  This doesn't sound too hard.

The hard part is all the subtitle formats:

1) Subtitles exposed by LAV Source / Splitter using the standard text pin
2) Sidecar files like .sub, .idx, .ssa, and about 20 other formats
3) Embedded subtitles that don't have a text pin (possibly the time-overlay on some home videos, etc.)
4) DVD subpicture information, which is encrypted (not really a subtitle, but not supported by madVR otherwise)
5) Line 21 information (currently we use a Microsoft Line 21 decoder)

Is it worth the time to create a custom subtitle system?  Is there an easier solution?

Thanks for any advice.

Well Matt, this was my feature request so you know my answer already ;-)

English is not my native tongue but in general I never use English subs when watching (and I watch every movie in original language). My collection consists of movies from all over the world. Lots of Criterion, many french, many asian. And as mentioned before - there are plenty of movies with forced subs for certain scenes. In short: subtitles are of prime importance for many reasons. And subtitle handling is a huge soft spot of HTPC playback. There is not a single solution that is really satisfactory.

I tight integration of LAVsplitter -> MC subtitle parser/renderer and -> madVR would be the final puzzle piece in many setups.

The mentioned problems are relevant and there are endless formats out there. You really open a can of worms when you try to deal with all of them. I would start by building the LAVsplitter->parser->madVR renderer and making sure PGS subtitles work in particular.

THANK YOU!
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SamuriHL

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Re: Subtitle rendering
« Reply #8 on: July 09, 2011, 11:51:53 am »

It would let me get rid of ffdshow from my setup once and for all.  :)  A sub renderer written properly would be just an amazing thing.
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gvanbrunt

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Re: Subtitle rendering
« Reply #9 on: July 09, 2011, 01:38:21 pm »

If there were any sub renderer that "just worked" with a wide variety of formats (both internal and external) I would love to know about it. No matter what I've tried I have to jump through hoops to make it work. For an HTPC and WAF setup it should work with anything, and that currently does not happen.

I think others are correct that that would be huge draw to MC. This is an issue in all other players and you would be the first with flawless support. Add that to the flawless Video and Audio setups, and you are in a league of your own...
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JimH

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Re: Subtitle rendering
« Reply #10 on: July 09, 2011, 02:00:32 pm »

It would let me get rid of ffdshow from my setup once and for all.  :)  A sub renderer written properly would be just an amazing thing.
If you have thoughts about how to write it properly, please share them.
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SamuriHL

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Re: Subtitle rendering
« Reply #11 on: July 09, 2011, 02:06:12 pm »

If you have thoughts about how to write it properly, please share them.

I don't.  It's an incredibly difficult task.  Which is why it's not done.  The DirectVobSub renderer has bugs and isn't complete.  The ffdshow subtitle renderer has bugs and isn't complete and lacks any developers to work on it.  Quite frankly I don't think your competition is going to come from those two areas.  What I see happening is that ArcSoft is getting into the game.  They can now bitstream MKV's.  The next logical step is to add better subtitle support.  Who knows when that'll happen, but, it's a pretty safe bet that it will at some point.  Something that works with madVR like the internal version of DirectVobSub that MPC-HC uses would be ideal.  Modularized so that formats could be easily added.  It will be very challenging.
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gvanbrunt

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Re: Subtitle rendering
« Reply #12 on: July 09, 2011, 08:08:31 pm »

My complaint with current renderers is they are not smart enough to use external subs, no matter where they are. No matter how I set things up, I have to reconfigure it every so often. For example for external subs I'll set it up for a subdirectory called subs. Then I'll import some movie that I don't intend to keep forever and just want to watch it. It has the Subs in a directory called Subtitles. So I have to mess around with the settings just to watch that one movie.

If the sub renderer were "smart" it could get the sub location from the player (MC), which would locate the subs location on import. Then no more hastles for external subs...
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