Foreign Audio Search ?

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PierU
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Joined: Sat Feb 16, 2019 2:28 pm

Foreign Audio Search ?

Post by PierU » Sat Feb 16, 2019 3:01 pm

Hi,

After years of using HB, I still don't use "Foreign Audio Search" because I don't understand clearly what it is supposed to do...

What I have understood :
- some DVDs have a special subtitle track, in the same langage than the main langage of the DVD, that displays subtitles when necessary (for instance if french is spoken in a particular scene in an english spoken DVD).
- This track can be selected and possibly burnt or defined as default
- If such a track is not physically present and if "forced" is checked for the Foreign Audio Search selection, then Handbrake scans the subtitle tracks that correspond to the main langage and creates a track by using the forced sections only.

Questions :

1) how is defined the "main langage" ? Is it defined on the DVD ? Is it defined by the first audio track selected in HandBrake ?

2) when this track physically exists, it is visible in players such as VLC or it is hidden ? It visible, does it appear as a standard track ?

3) what is the difference with the classical subtitle tracks that are marked [forced] ?

4) what if one selects several audio tracks with different langages ? I want to both the native audio track and the french dubbing is available : how can I get forced-only subtitles for both audio with the Foreign Audio Search fonction ?

Sorry if I'm not clear, but the topic is not clear to me !

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JohnAStebbins
HandBrake Team
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Re: Foreign Audio Search ?

Post by JohnAStebbins » Sat Feb 16, 2019 3:53 pm

First let me restate how foreign audio search works.

If the "main language" matches your "preferred language" a list of all subtitle tracks that are in your preferred language is created. The subtitles in this list are scanned and the frequency of occurrence of subtitles is compared between the tracks. If a track is found that has less than 10% of the subtitles of the track that has the most subtitles, that track is chosen as the "foreign audio" subtitle track *unless* you checked the forced checkbox *and* a track was found with forced subtitles, in which case the track with forced subtitles is chosen.

To answer your questions:
1. The main language, is the language the characters in the video are speaking for the majority of the scenes. HandBrake determines this based on the audio tracks. It assumes that the primary language being spoken is the language of the first audio track. I've never seen a case where this is incorrect, but in theory, this assumption can be wrong.
2. When it's a separate track, it appears as a normal subtitle track.
3. DVD and BD subtitle tracks may have subtitles within the track that have been marked forced. To be clear, the track is *not* marked forced, individual subtitles within a track have a forced flag associated with them. The force flag is used for various things, but most often it is used to force a subtitle to appear during a foreign language scene. DVD and BD use this forced flag in conjunction with a "default" subtitle track setting that causes the track to be selected automatically during playback so that the subtitles are displayed during foreign language scenes. A "selected" track is not necessarily a "visible" track. These are different settings, but forced subtitles within the "selected" track are always "visible". When doing "foreign audio search" HandBrake prefers subtitles marked forced over tracks that have no forced subtitles *if* you have checked the "forced" checkbox. If you have not checked the forced checkbox, HandBrake ignores the forced flags.
4. I don't understand your last question, but I'll see if I can clarify some behavior. Foreign audio search should follow the above rules to find a matching track. If a match is found, it is added as the first subtitle tracck in your output. If you checked forced and the match had forced subtitles, only forced subtitles will be written to that output track. All the other tracks you specify after "foreign audio search" should be written to the output file as you specify in the options to each of those tracks. Adding a subtitle track to your output selection with the forced checkbox checked will create an output track that has only the forced subtitles from the source track you selected.

PierU
Posts: 3
Joined: Sat Feb 16, 2019 2:28 pm

Re: Foreign Audio Search ?

Post by PierU » Sat Feb 16, 2019 10:33 pm

OK, that indeed clarifies...

My last question was actually related to the case where several audio tracks are available in different langages. Say english (native) and french (dubbed), and I want to keep both audio in the rip.

First, how are the foreign langage sections managed on the DVD itself ? These sections are supposed to be different for each audio track, so elaborating on your answer 3, is there a different default subtitle track associated to each audio track ?

Then with HandBrake : according to your description, the FAS of HandBrake does its job for one langage only : in my case it would be english (first audio track/main langage of the DVD). So how to generate a foreign audio subtitle track for the french audio track as well ?

But actually I now can't see the point of FAS at all...
- If there exists a specific subtitle track for the foreign audio sections of a langage one just have to rip it
- otherwise one have to rip the full subtitle track of that langage with the "forced only" option.

Am I correct ?

Woodstock
Veteran User
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Joined: Tue Aug 27, 2013 6:39 am

Re: Foreign Audio Search ?

Post by Woodstock » Sat Feb 16, 2019 11:53 pm

How tracks are managed is up to the DVD (or BD) author. They decide whether subtitles in language "x" are a single track with flags in the track, a single track with no in-track flags, or separate tracks, selected via menu entries on the disk.

The point of FAS is that it does work for perhaps 90% of movie-type video. For those of us that do well without it, it can seem pointless, but we're "edge cases". I can come up with many places where FAS can fail.

Yes, FAS is limited to dealing with a single language; not many people want to see the "foreign audio" in a language other than their own. I have titles that are subtitled in as many as a dozen languages, dubbed in 5 of them. With my language settings (favor English, Japanese), the Chinese, Malay, French, and Spanish subtitles are not going to be considered by FAS.

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JohnAStebbins
HandBrake Team
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Re: Foreign Audio Search ?

Post by JohnAStebbins » Sun Feb 17, 2019 2:57 am

The point of FAS is you don't know which track has the subtitles for foreign audio scenes without doing some kind of search. To use your words, if there exists a specific track for foreign audio sections, which track is it? If FAS didn't exist, how would *you* determine which track to add to your encode to obtain foreign audio subtitles? There is no marker in the DVD metadata to tell you which track this might be or if such a track exists at all. You must search for it. If there is a track with forced subtitles, which track is it? Again, it's not marked in the DVD metadata, you must search for it and there may be *none*.

PierU
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Joined: Sat Feb 16, 2019 2:28 pm

Re: Foreign Audio Search ?

Post by PierU » Sun Feb 17, 2019 9:07 am

JohnAStebbins wrote:
Sun Feb 17, 2019 2:57 am
The point of FAS is you don't know which track has the subtitles for foreign audio scenes without doing some kind of search. To use your words, if there exists a specific track for foreign audio sections, which track is it? If FAS didn't exist, how would *you* determine which track to add to your encode to obtain foreign audio subtitles? There is no marker in the DVD metadata to tell you which track this might be or if such a track exists at all. You must search for it. If there is a track with forced subtitles, which track is it? Again, it's not marked in the DVD metadata, you must search for it and there may be *none*.
I agree. In practice when there are several subtitles tracks for a given audio langage, I first quickly browse them in VLC to check what they do contain. I understand now that FAS can do this automatically for me, but only for one langage (and I usually keep two audio tracks (or more)), so I would have to browse the subtitles anyway...

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