How to make soft subs?

[User35785]

Hello,

What tools do I need to make and view softsubs with plain avi files? So far I have only been able to find info about hard-coded subtitles. I don't want to modify in any way my files, so no recoding to MKV of similar container formats.

[Sylf]

Making softsub requires some kind of recoding, as long as you want to keep the file in one piece. If you don't mind having an AVI file and subtitle file separately, then it's easy.

Two File Method
Make a subtitle file using programs such as aegisub, sabbu, substation alpha, medusa, and save it with same name as AVI file. i.e. MyVideo.avi and MyVideo.ass. Put two files in the same directory. Make sure you have VSFilter installed on your system. Play back the AVI using your favorite DirectShow based media player (MPC, etc), and VSFilter will overlay the sub automatically.

Recoding Method
Make subtitle just like the previous method. Use AVI-Mux GUI. Drop in the AVI file and ASS/SSA file on that window. Mux. You can use either AVI or MKV with this tool. The video itself will be left untouched - it's just in a new container too. MKV is a much better format than AVI.

[User35785]

I think I'll go for the two file method - thanks for your precious help!

[Zero1]

You could always mux a SRT to AVI, but you only get basic functionality with the SRT format, plus it's a bit of a no-no. Bah, what the hell, AVI is hacked enough as it is, why should softsubs bother people now Heh.

Edit:
Just realised that Sylf pretty much already covered what I wanted to say, that's posting on a mobile phone with a 176x208 screen for ya...

Anyway, the last time I tried it, I don't recall SSA working when muxed to AVI, which I find strange.

By the way SHIRAKAWA Akira, the two processes have specific names. Encoding/Transcoding and Multiplexing/Transmultiplexing also known as Muxing/Transmuxing.

Transcoding is the re-encoding of a file, often to a different compressor (codec), or specific filesize. A common example is encoding DVD MPEG-2 (from it's VOB program stream) to something much smaller in size for internal distro for use as a work raw. This particular transcode implies a different filesize and compression standard, and is quite common. Another, is transcoding of a fansub raw to a work raw, that might even use the same codec, but just a lower filesize is required. The final distro usually undergoes the same or similar process as creating the raws, but done at a higher quality. Same sort of transcode essentially.

Transcoding with lossy codecs such as MPEG-4, specifically DivX and XviD (which don't have lossless modes) always implies a quality loss, termed as generation loss. This is due to a combination of DCT and Quantisation (or more specifically re-encoding to a lower bitrate, or using a different quantisation matrix). Lossless codecs such as HuffYV12 and Lagarith avoid this generation loss, but are obviously not practical for distribution.


Muxing is the process of taking some raw streams, such as a video and audio track, possibly a subtitle file and putting them together in a container, for example AVI, MKV, MP4 or even OGM *shudder*. Muxing is done transparently, automatically in Virtualdub, it's something you simply don't see or have to deal with, though it is possible to make adjusments to certain settings regarding muxing, such as audio delay, interleaving etc. Additionally with Virtualdubmod you can encode your audio externally using the LAME MP3 CLI and add the stream later in Virtualdubmod, you might refer to this as user friendly muxing. A time when you would need to mux files from scratch would be for example if you encoded some raw H.264 using the x264 CLI, and encoded your audio seperately in FAAC, or AoTuV Vorbis for example. You would need a way to get these multiple files into a single playable file, and muxing is what does that. Both MKV and MP4 have specialised tools for muxing, I wouldn't know about OGM because it was outclassed by MKV which offers most of if not all of OGM's "features" and isn't a practically unseekable like OGM.

Transmuxing, to all intents and purposes is a similar job as Muxing, but rather than starting off with your raw files and putting them to a playable format, you start with one playable format, extract the streams, and place them into an alternative playable format. A prime example of this is transmuxing AVI to MKV or MP4, MP4 to MKV, MKV to MP4 or OGM to AVI or MKV. There are a large number of possibilites, but you need to be aware of the pros and cons of each format, as well as their capabilities. For example transmuxing an MKV containing H.264 and Vorbis to MP4 is no good, because MP4 is not designed to contain Vorbis (it can, but it's a bad, hackish and unsupported idea). You would need to transcode the audio to AAC or MP3, which obviously lowers the quality. Similarly, you cannot (or should not) transmux a dual audio MP4 or MKV, with softsubs to AVI, since AVI isn't designed to handle multiple audio streams (though DivX has created the .divx format which is a hacked or "extended" AVI, which does handle multiple audo streams). MP4 has it's own softsub format, called 3GP timed text. AVI cannot understand this, last I knew it was not possible to mux this to MKV either, so as you can see, you have possibilies, but you are limited by the capabilites of the formats.

Muxing and/or transmuxing is as you might have guessed, a lossless procedure since all you do is place the data into a format that is playable, or move it to another format. You never actually touch the encode, so the quality is not affected. One thing you might notice though is filesize. Since MKV and MP4 are more efficient than AVI, if you were to transmux the contents of an AVI to MKV or MP4, you might have 2-5MB per episode. Could be useful for when a group overshoots the CD/DVD size by just a few MB.