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Skip if the video already contains graphical subtitles


jwill
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jwill

In MBS 5264, it adds subtitles and one option is a checkbox to "Skip if the video already contains graphical subtitles".

 

Would you please explain what exactly is meant by "video already contains graphical subtitles"?

 

If the word 'graphical' were not present, I would assume it meant that if the video file already contains a subtitle track, then skip downloading subtitles.

 

But "graphical subtitles" perhaps means something different. It is possible to include .srt (textual) subtitles in an MKV file. Am I to assume if an MKV file contains no other subtitles except .srt subtitles, then it does not count as "graphical subtitles" and MBS would download subtitles even if this box is checked?  :huh:

Edited by jwill
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jwill

Burned in subtitles maybe?

If subtitles are burned into the video, how would MBS be able to tell? Some sort of OCR?  :huh:

 

I guess that is NOT what is meant here.

Edited by jwill
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FrostByte

If the video contained burned in subtitles I would want MB to skip downloading subtitles though because it can't see them when they are burned in and they would be unneeded at that point.  You could be right though

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Koleckai Silvestri

DVDs and Blurays often have PGS subtitles. This stands for Presentation Graphics Stream. These are are graphical images that are overlayed on top of the video stream during the playback of the media. This is why the subtitles can lose their anti-aliasing when you zoom in on the video. Some people call these "burnt in". Which is true with MP4. You can't turn Burnt In subtitles on or off because they become part of the video stream. If you use MKV, they remain their own separate stream.

 

Broadcast Television (and Web Television) on the other hand include the subtitles as a text file that is transformed into an overlay with a font on top of the video stream.

 

Systems like MediaBrowser can apply the text based subtitles to media even if they don't have it originally. However if you have one, you don't necessarily need the other.

 

MediaBrowser can tell if you have "Burnt" in subtitles by looking at the codec specified by the different stream within the container. Some containers like MP4 can't include subtitles in a separate stream though so systems create different streams with or without the subtitles before you download them.

Edited by Wayne Luke
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jwill

I am aware of what PGS subtitles are. That does not answer my question. Is MBS making a distinction between, for example, embedded SRT subtitles and embedded PGS subtitles? If so, why? (It does not seem to make sense to NOT download SRT subtitles if we have embedded PGS subtitles, but DO download SRT subtitles if we have embedded SRT subtitles)

Edited by jwill
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Koleckai Silvestri

Looking at the help text it says that text subtitles are more efficient. Seems while the option is there to disable it, it is recommended to leave it off if you use mobile a lot. On the other hand if you're tight for space, you can save a small amount here.

 

As for existing SRT subtitles in the system, it can simply skip those media files altogether just by reading the information of the streams. As you said there is no reason to download an SRT subtitle if you already have one in the same language. Are you experiencing the download of subtitles if they already exist as in the container?

Edited by Wayne Luke
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jwill

Looking at the help text it says that text subtitles are more efficient. Seems while the option is there to disable it, it is recommended to leave it off if you use mobile a lot. On the other hand if you're tight for space, you can save a small amount here.

 

As for existing SRT subtitles in the system, it can simply skip those media files altogether just by reading the information of the streams. As you said there is no reason to download an SRT subtitle if you already have one in the same language.

 

You are still not following my question. It might make sense to download SRT subtitles if the only embedded subtitles are PGS, and not download SRT subtitles if there are already embedded SRT subtitles. BUT THAT IS NOT WHAT THIS OPTION APPEARS TO DO. It seems to do the opposite -- not download SRT subtitles if there are "graphical subtitles" already there.

 

I do not think we are getting anywhere in this discussion.

 

Hopefully someone who has looked at (or written) the code for subtitles will respond with an explanation.

Edited by jwill
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Koleckai Silvestri

If you want to download the SRT subtitles, you leave the option Off.

 

If you are worried about space and internet bandwidth, you turn the option On to avoid downloading the extra subtitles you might not need.

 

This is in line with other metadata downloads that you might want to change to control your internet bandwidth. Wording could probably be better though.

Edited by Wayne Luke
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jwill

If you want to download the SRT subtitles, you leave the option Off.

 

If you are worried about space and internet bandwidth, you turn the option On to avoid downloading the extra subtitles you might not need.

 

This is in line with other metadata downloads that you might want to change to control your internet bandwidth. Wording could probably be better though.

 

You still have not answered my question. Unless you are familiar with the code and can definitively answer my simple question (what EXACTLY constitutes 'video already contains graphical subtitles'?), then please stop responding, and let someone who is familiar with the code give an explanation.

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Koleckai Silvestri

Sure thing. You obviously don't know about media streams and containers. Good luck in your future endeavors.

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jwill

 You obviously don't know about media streams and containers. 

 

Actually, I do know about media streams and containers -- hence my question. 

 

My question was quite clearly stated both in my original post, and in my previous post to this one. It remains unanswered. I will await someone who is familiar with the MBS code for subtitles to answer my simple question.

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Actually, I do know about media streams and containers -- hence my question. 

 

My question was quite clearly stated both in my original post, and in my previous post to this one. It remains unanswered. I will await someone who is familiar with the MBS code for subtitles to answer my simple question.

 

Good day,

 

As I understand it, it any subtitle that "indicated" to the media browser server as "internal" either within video file (vob .. etc) or the container format (mkv, mp4,  .. etc), but really I am with you here, your question is very good one.

 

So to Media Browser server internal no matters what format file that subtitles are (text / images) are within graphical term here.

 

Luke the head dev's personals of the media browser 3 project as well Tikuf, they can indeed answer this in the correct/tech way as code writer.

 

My best

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I haven't done any work on this but I just looked at the code and this option will skip downloading if the item in question contains internal subs of either the 'pgs' or 'dvd' codec in the language being requested.

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Yup. I think you guys kind of figured it out and the help text explains why it can be advantageous to have text versions even if the video already has pgs.

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jwill

I haven't done any work on this but I just looked at the code and this option will skip downloading if the item in question contains internal subs of either the 'pgs' or 'dvd' codec in the language being requested.

 

So, it specifically looks for PGS or VobSub embedded subtitles, but specifically does NOT look for SRT embedded subtitles?

 

Do you see why I said that does not make sense to me? No? I'll explain again.

 

If the box is checked, and we have an MKV file with embedded SRT subtitles, then MBS will download an SRT subtitle file. On the other hand, if the box is checked and we have an MKV file with embedded PGS subtitles, then MBS will NOT download an SRT subtitle file.

 

Why would this be desired behavior? Why would we want SRT subtitles downloaded if there are embedded SRT subtitles, but NOT want SRT subtitles downloaded if there are embedded PGS subtitles?

 

If SRT subtitles are more efficient in some instances, it seems to me we would want the opposite behavior. Download SRT subtitles if there are NOT embedded SRT subtitles (only PGS or VobSub), but do NOT download SRT subtitles if there are already embedded SRT subtitles. 

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