From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laura Lazzati Subject: Video subtitles Date: Wed, 19 Dec 2018 22:55:34 -0300 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Return-path: Received: from eggs.gnu.org ([2001:4830:134:3::10]:58993) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gZnZd-00067p-Gi for guix-devel@gnu.org; Wed, 19 Dec 2018 20:56:30 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gZnZb-00043Y-AE for guix-devel@gnu.org; Wed, 19 Dec 2018 20:56:29 -0500 List-Id: "Development of GNU Guix and the GNU System distribution." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guix-devel-bounces+gcggd-guix-devel=m.gmane.org@gnu.org Sender: "Guix-devel" To: Guix-devel Cc: Ricardo Wurmus Hi! I have been playing with aegisub today and I would like to share my experience with that tool, your ideas about how video subtitles should be included, and your advice too. I installed aegisub from guix, and when I open it, it has a GUI. There you load your video, in my case I loaded the final video - the one everybody loved with Dennis pics, that already had my voice - and started from there. And ended up with a a final video with subtitles included. But don't stop reading here. 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 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. 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 Bj=C3=B6rn tomorrow to upload it to their IPFS so that you can see what I mean. 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. I find a solution for not getting the whole text of the subtitle at once, that is creating each svg/cli session/whatever appears-in-the-video-if-needed with their audio and subtitle separately and glue every piece of video as a last step with ffmpeg. Apparently, that is possible according to https://trac.ffmpeg.org/wiki/Concatenate - have not tried it yet. However, I don't know if, in case of wanting to have the subtitles separately - not hardsubs- in this latter case if it is possible to concatenate them and use them outside the video. Sorry if the mail is too long, or if sth is messy, please, let me know. Regards :) Laura