There is a lot of confusion (see for example THIS) around Closed Captions (CC for short); they are routinely mistaken for traditional, textual subtitles (subs for short), even in the non-TV-streaming / DVD, that is, strictly Apple world. In this article, I've elaborate on the difference, the CC-to-subs conversion and the rendering of the original (Apple) CC's in desktop and iOS players.
1. The difference between CC and textual subs
1.1 Apple's CC
First and foremost, everything you purchase or download from Apple's iTunes Store have CC subtitles only (if at all): both movies you do pay for (the minority of the paid movies, unfortunately) and the free iTunes University videos; for example, the ones HERE (the Stanford U iOS programming course). You can easily see, before purchasing, if a given title has CC's: just look for the CC icon. For example, in the above iTunes U example, all non-slide downloads have CC's. I've annotated some of the first ones:
With non-iTunes U movies, the CC icon is in the left side:
Of the former iTunes U videos (more specifically, of the second in the list), I've created a chunk, available for download HERE; of the latter (1080p Full HD Men in Black II), HERE. For creating the latter, I used QuickTime Pro 7 on an authorized desktop computer. The former could have been created on any (not necessarily authorized) computer with QuickTime Pro 7.
1.1.1 Editing (cut / copy) DRM'ed videos in QuickTime 7 Pro
A side note on how I've created the latter video (An editing and iOS playback trick):
In QT7 Pro, after copying a slice of the DRM'ed video to the clipboard, when you create a new video and paste the content of the clipboard into it, it'll state it's not authorized to play it back. However, you can save it without problems. The embedded CC track will also be saved and the resulting file will be playable in iTunes on an authorized computer or iDevice. The latter, of course, will only allow for playing the file back from the stock Videos app or, if the device is jailbroken, the uppermost Video Player item in the absolutely essential jailbreak file handler tool iFile:
(as with all images below, click the thumbnail for a much better-quality and larger one!)
Should you want to avoid having to synchronize your DRM'ed videos to your iDevice via iTunes and would prefer copying them via iTunes File Sharing, this is an excellent workaround. Or, for that matter, keep on an SD card or other kind of similar mass memory (see THIS for info on using Apple's Camera Connection Kit for this) This means you do not need to store your movies you've purchased from Apple you can just copy them to, say, an SD card and use iFile's player to play them back.
Note that I've also explained this in THIS MacRumors thread.
1.1.2 Enabling CC rendering in Apple's operating systems
1.1.2.1 Apple CC's
The (Apple) CC's in Apple's iTunes Store / University movies are rendered by Apple's all players. For example, the desktop iTunes presents you with an icon (annotated with a red rectangle):
In QuickTime X coming with recent OS X versions, there's no any kind of icon you need to en/disable CC rendering in its menu, via View > Show [Hide] Closed Captioning.
There's no icon in the stock Videos player under iOS either. There, you must enable CC rendering separately, in the system-level Settings app. Go to Settings > Videos and enable Closed Captioning (annotated):
Again, there are no icons to tap on the Videos interface, unlike with textual (non-Apple) subtracks. This is what Videos' interface looks like while playing back a video with a(n Apple) CC track:
Compare the above interface screenshot to that of Videos playing back a video with a true non-CC textual subtrack; notice the text bubble icon annotated by a red rectangle:
1.1.2.2 ATSC CC's
As has already been mentioned, currently, you in no way can display ATSC CC's in any player under iOS (as opposed to the Apple CC's) - you absolutely must transcode all those videos to a MOV (via, say, HandBrake), convert the original CC's to SRT's (Chapter 2.) and, finally, embed the SRT in the MOV (Chapter 3.).
On desktop operating systems, the situation isn't that bad: the excellent, free VLC displays these CC's just fine (after enabling them under Video > Subtitles Track). Apple's own players don't fare very good, though: iTunes and QuickTime Pro 7 can't play TS files back at all; under Mountain Lion (OS X 10.8), QuickTime Player X can - but without the CC's. (The "Show Closed Captions" menu item is grayed out.)
1.1.3 Rendering difference between the two approaches
1.1.3.1 In Apple's players
In addition to being presented an separate icon for subtrack enabling (and selecting between them, if there are more than one of the subtracks), it's very easy to spot the difference between them based on the way they're rendered.
If you see non-proportional (read: pretty ugly), non-resizable text on black background, it's CC:
(desktop QT player)
(Videos player on iPhone 5)
And if it looks much better (neat, proportional font, without the ugly background), then, it's (non-Apple) textual. An iPhone 5 example, showing THIS video (the output of Subler the one we'll create below):
Note that the iPad (as opposed to the iPhone) even draws a somewhat darker background behind the textual subtitle, making it even easier to read, even over very bright / white video:
iPads render Apple CC's in exactly the same way as iPhones (ugly fonts etc.); that is, they lose the advantage of the better background they apply to textual subs.
1.1.3.2 In MediaInfo
A quick look at the excellent, free and, therefore, highly recommended MediaInfo also helps differentiating between the two technology.
With traditional text tracks, you'll see Timed text as the Text stream type:
With CC's, you'll always see EIA-608 as the type:
1.2 CC's in ATSC broadcast recordings
ATSC, used for broadcasting digital TV in North-America and some other areas of the world, also uses CC's for subtitles. Note: In the areas where DVB is used instead of ATSC for digital TV broadcasting, generally, bitmap subtitles are used instead. Some iOS players (for example, GoodPlayer) are able to render them natively; you can easily extract them from the original TS recordings via ProjectX as traditional VobSub bitmap subtitles and add them to the target file (even Apple's native MOV / M4V / MP4's). The workflow of the latter is explained HERE and has absolutely nothing to do with the one for CC's. Note that the difference between the States (+Canada + some other states) and the rest of the world is also present when it comes to DVD's: in the US, they commonly use texual CC tracks; elsewhere, bitmap VobSubs. DVD CC's, as I don't have access to US DVD's with CC's here in Europe, are not discussed in this article. Basically, you can use the same CCExtractor (see below) to convert them to SRT's directly embeddable into most video containers and rendered by even Apple's players.
Unfortunately, as opposed to the Apple CC case (see above) none of the current iOS players render these ATSC CC's so, should you want to see them, you absolutely must extract the CC's and convert them to something more widely supported (e.g., SRT's). This will be discussed in the next chapter.
An example of these ATSC recordings is HERE (unzip it!). I will use it in the subsequent examples & tutorials.
2. Extracting CC's from the original files using CCExtractor
If you're happy with the way Apple CC's are played back on iOS, this (and the following) chapter won't be for you. However, if you want to resize / reposition them (in some, more capable third-party players) and/or just want them to be rendered using a much more pleasant font (and, on the iPad, an additional, dark background), you'll want to convert them to textual subs. (With ATSC CC files, as no player renders them currently, this is the only way of making them readable.)
This conversion has two steps:
- converting the CC's to SRT's via CCExtractor (the subject of this chapter)
- embedding the resulting SRT in the MOV file (the subject of the next chapter)
CCExtractor is a great, free, Windows-only (works just fine under Parallels & Win7) tool you WILL want to use to extract and convert CC's to textual SRT subs. Not only with Apple's CC's (assuming you want to convert unprotected videos; for example, those of the iTunes U because of, say, their awful rendering and fonts), but also with ATSC TS recordings.
Using it is pretty easy to learn. Generally, you drag the input file(s) to the Input files pane:
(Here, I've dragged the iTunes U chunk I've introduced in Section 1.1).
Now, after making some input format-specific (see the sections immediately below) switch to the Execute tab and click Start. The following screenshot shows the annotated button after clicking it and the apps' finishing execution, correctly finding the CC's in the input file (see the window, showing the finished output, just above the Start button):
Note that, almost surely, you'll need to play with some settings in both the Apple and the ATSC case before actually clicking Start. In the following subsections, I explain what additional settings need to be done.
2.1 Custom settings of Apple's own CC format
If you need to convert Apple's CC's, make absolutely sure you do select MP4 in the Input options tab as auto-detecting will fail:
Note: nothing can process protected Apple videos: it'll state Found no AVC track(s). found no dedicated CC track(s). That is, you can't extract CC's from a protected video purchased from iTunes.
2.2 Generic ATSC format
With a lot of videos, you will need to disable Teletext processing for ATSC recordings:
2.2.1 Roll-up captions
You might also want to disable roll-up captions (which are very commonly used in ATSC broadcasting) to avoid text duplication clearly visible in the following screenshot (see the duplicated, line-by-line upwards-shifted lines in the annotated output area):
Just enable the following checkbox in the Output (2) tab:
Then, the output won't have any duplicated rows:
(continued below!)
1. The difference between CC and textual subs
1.1 Apple's CC
First and foremost, everything you purchase or download from Apple's iTunes Store have CC subtitles only (if at all): both movies you do pay for (the minority of the paid movies, unfortunately) and the free iTunes University videos; for example, the ones HERE (the Stanford U iOS programming course). You can easily see, before purchasing, if a given title has CC's: just look for the CC icon. For example, in the above iTunes U example, all non-slide downloads have CC's. I've annotated some of the first ones:
With non-iTunes U movies, the CC icon is in the left side:
Of the former iTunes U videos (more specifically, of the second in the list), I've created a chunk, available for download HERE; of the latter (1080p Full HD Men in Black II), HERE. For creating the latter, I used QuickTime Pro 7 on an authorized desktop computer. The former could have been created on any (not necessarily authorized) computer with QuickTime Pro 7.
1.1.1 Editing (cut / copy) DRM'ed videos in QuickTime 7 Pro
A side note on how I've created the latter video (An editing and iOS playback trick):
In QT7 Pro, after copying a slice of the DRM'ed video to the clipboard, when you create a new video and paste the content of the clipboard into it, it'll state it's not authorized to play it back. However, you can save it without problems. The embedded CC track will also be saved and the resulting file will be playable in iTunes on an authorized computer or iDevice. The latter, of course, will only allow for playing the file back from the stock Videos app or, if the device is jailbroken, the uppermost Video Player item in the absolutely essential jailbreak file handler tool iFile:
(as with all images below, click the thumbnail for a much better-quality and larger one!)
Should you want to avoid having to synchronize your DRM'ed videos to your iDevice via iTunes and would prefer copying them via iTunes File Sharing, this is an excellent workaround. Or, for that matter, keep on an SD card or other kind of similar mass memory (see THIS for info on using Apple's Camera Connection Kit for this) This means you do not need to store your movies you've purchased from Apple you can just copy them to, say, an SD card and use iFile's player to play them back.
Note that I've also explained this in THIS MacRumors thread.
1.1.2 Enabling CC rendering in Apple's operating systems
1.1.2.1 Apple CC's
The (Apple) CC's in Apple's iTunes Store / University movies are rendered by Apple's all players. For example, the desktop iTunes presents you with an icon (annotated with a red rectangle):
In QuickTime X coming with recent OS X versions, there's no any kind of icon you need to en/disable CC rendering in its menu, via View > Show [Hide] Closed Captioning.
There's no icon in the stock Videos player under iOS either. There, you must enable CC rendering separately, in the system-level Settings app. Go to Settings > Videos and enable Closed Captioning (annotated):
Again, there are no icons to tap on the Videos interface, unlike with textual (non-Apple) subtracks. This is what Videos' interface looks like while playing back a video with a(n Apple) CC track:
Compare the above interface screenshot to that of Videos playing back a video with a true non-CC textual subtrack; notice the text bubble icon annotated by a red rectangle:
1.1.2.2 ATSC CC's
As has already been mentioned, currently, you in no way can display ATSC CC's in any player under iOS (as opposed to the Apple CC's) - you absolutely must transcode all those videos to a MOV (via, say, HandBrake), convert the original CC's to SRT's (Chapter 2.) and, finally, embed the SRT in the MOV (Chapter 3.).
On desktop operating systems, the situation isn't that bad: the excellent, free VLC displays these CC's just fine (after enabling them under Video > Subtitles Track). Apple's own players don't fare very good, though: iTunes and QuickTime Pro 7 can't play TS files back at all; under Mountain Lion (OS X 10.8), QuickTime Player X can - but without the CC's. (The "Show Closed Captions" menu item is grayed out.)
1.1.3 Rendering difference between the two approaches
1.1.3.1 In Apple's players
In addition to being presented an separate icon for subtrack enabling (and selecting between them, if there are more than one of the subtracks), it's very easy to spot the difference between them based on the way they're rendered.
If you see non-proportional (read: pretty ugly), non-resizable text on black background, it's CC:
(desktop QT player)
(Videos player on iPhone 5)
And if it looks much better (neat, proportional font, without the ugly background), then, it's (non-Apple) textual. An iPhone 5 example, showing THIS video (the output of Subler the one we'll create below):
Note that the iPad (as opposed to the iPhone) even draws a somewhat darker background behind the textual subtitle, making it even easier to read, even over very bright / white video:
iPads render Apple CC's in exactly the same way as iPhones (ugly fonts etc.); that is, they lose the advantage of the better background they apply to textual subs.
1.1.3.2 In MediaInfo
A quick look at the excellent, free and, therefore, highly recommended MediaInfo also helps differentiating between the two technology.
With traditional text tracks, you'll see Timed text as the Text stream type:
With CC's, you'll always see EIA-608 as the type:
1.2 CC's in ATSC broadcast recordings
ATSC, used for broadcasting digital TV in North-America and some other areas of the world, also uses CC's for subtitles. Note: In the areas where DVB is used instead of ATSC for digital TV broadcasting, generally, bitmap subtitles are used instead. Some iOS players (for example, GoodPlayer) are able to render them natively; you can easily extract them from the original TS recordings via ProjectX as traditional VobSub bitmap subtitles and add them to the target file (even Apple's native MOV / M4V / MP4's). The workflow of the latter is explained HERE and has absolutely nothing to do with the one for CC's. Note that the difference between the States (+Canada + some other states) and the rest of the world is also present when it comes to DVD's: in the US, they commonly use texual CC tracks; elsewhere, bitmap VobSubs. DVD CC's, as I don't have access to US DVD's with CC's here in Europe, are not discussed in this article. Basically, you can use the same CCExtractor (see below) to convert them to SRT's directly embeddable into most video containers and rendered by even Apple's players.
Unfortunately, as opposed to the Apple CC case (see above) none of the current iOS players render these ATSC CC's so, should you want to see them, you absolutely must extract the CC's and convert them to something more widely supported (e.g., SRT's). This will be discussed in the next chapter.
An example of these ATSC recordings is HERE (unzip it!). I will use it in the subsequent examples & tutorials.
2. Extracting CC's from the original files using CCExtractor
If you're happy with the way Apple CC's are played back on iOS, this (and the following) chapter won't be for you. However, if you want to resize / reposition them (in some, more capable third-party players) and/or just want them to be rendered using a much more pleasant font (and, on the iPad, an additional, dark background), you'll want to convert them to textual subs. (With ATSC CC files, as no player renders them currently, this is the only way of making them readable.)
This conversion has two steps:
- converting the CC's to SRT's via CCExtractor (the subject of this chapter)
- embedding the resulting SRT in the MOV file (the subject of the next chapter)
CCExtractor is a great, free, Windows-only (works just fine under Parallels & Win7) tool you WILL want to use to extract and convert CC's to textual SRT subs. Not only with Apple's CC's (assuming you want to convert unprotected videos; for example, those of the iTunes U because of, say, their awful rendering and fonts), but also with ATSC TS recordings.
Using it is pretty easy to learn. Generally, you drag the input file(s) to the Input files pane:
(Here, I've dragged the iTunes U chunk I've introduced in Section 1.1).
Now, after making some input format-specific (see the sections immediately below) switch to the Execute tab and click Start. The following screenshot shows the annotated button after clicking it and the apps' finishing execution, correctly finding the CC's in the input file (see the window, showing the finished output, just above the Start button):
Note that, almost surely, you'll need to play with some settings in both the Apple and the ATSC case before actually clicking Start. In the following subsections, I explain what additional settings need to be done.
2.1 Custom settings of Apple's own CC format
If you need to convert Apple's CC's, make absolutely sure you do select MP4 in the Input options tab as auto-detecting will fail:
Note: nothing can process protected Apple videos: it'll state Found no AVC track(s). found no dedicated CC track(s). That is, you can't extract CC's from a protected video purchased from iTunes.
2.2 Generic ATSC format
With a lot of videos, you will need to disable Teletext processing for ATSC recordings:
2.2.1 Roll-up captions
You might also want to disable roll-up captions (which are very commonly used in ATSC broadcasting) to avoid text duplication clearly visible in the following screenshot (see the duplicated, line-by-line upwards-shifted lines in the annotated output area):
Just enable the following checkbox in the Output (2) tab:
Then, the output won't have any duplicated rows:
(continued below!)
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