Hello, Ricardo Wurmus <[email protected]> ezt írta (időpont: 2018. dec. 20., Cs, 9:26): > > > Hi Laura, > > > The first question I need to answer is if subtitles are going to be > > present all the time as part of the video, or they should be able to > > be disabled. We had that discussion somewhere, but if they are going > > to be present as part of the video (hardsubs) only .srt and .ass - the > > ones created by default by aegisub - are supported by ffmpeg: > > https://trac.ffmpeg.org/wiki/HowToBurnSubtitlesIntoVideo > > The subtitles should be provided as a separate file, so that they can > easily be swapped out or disabled. Some container formats allow > embedding the subtitles, but we would need to embed all subtitles in all > language variants of all video files, and this seems like more work. > Having the subtitles as separate files is more convenient for > processing. >
Yes, and the embeding into the container can be automated at the end if needed. > > I remembered how much time each audio file lasted, so I added one > > subtitle for each svg file that appears in the video - they were just > > three- with the full content of what is said in the audio. > > It is more common to have a single subtitle file per video. It would be ok to have a single subtitle file. > > > The drawback of this is that each svg file in the video has the full > > subtitle text before the speaker mentions those words - I will ask > > Björn tomorrow to upload it to their IPFS so that you can see what I > > mean. > > You can time the appearance of text. I’ve only ever written srt > subtitle files by hand before, but they are all similar in that they > associate a piece of text with a timestamp. The text is then displayed > at the specified time only. > > You can figure out the appropriate timestamps by playing back the video > and recording the times when something is said that should be titled. > So to make this more explicit, you could break down the text to smaller chunks, then time the appearance of those. > > When choosing the format of the subtitles, Ricardo mentioned that it > > was better using usf because it had support for styling. The good news > > is that aegisub allows us to do so in their own interface, but in > > their .ass format, one of the two that supports ffmpeg, which is not > > compatible, I guess, with the formats mentioned in po4a for > > translation. However the .ass subtitle can be exported as .ttxt - > > which is an XML, and that can be converted back to .ass. > > “.ass” files are very popular and very rich in styling features. “.usf” > files are less commonly seen in the wild. > > I have no strong opinions about using “.usf”. “.ass” may just be fine. > Apparently, it can be converted to po files for translation with > “sub2po”, which is part of the “translate” toolkit. I have no > experience with this, and I think it would be better to use a format > that didn’t require even more tools to work with. > > This shouldn’t block you, though. It is fine to use Aegisub manually to > create the initial subtitle and then convert it to another format. > Aegisub does not need to be part of the automated process to compile the > videos. > > -- > Ricardo > > I believe that we don't want to do anything fancy with the subtitles, so I guess any format would be just fine, provided we have tool support. Best regards, g_bor
