From: Romain B. <to...@ra...> - 2012-04-27 07:53:58
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Hi Haris! First of all, there is a script here for creating a static video: http://liquidsoap.fm/doc-1.0.0/video-static.html 2012/4/24 Haris Zukanovic <har...@gm...>: > ..and thank you very much for this detail of introduction :) > a couple of comments and questions below.. > > On 24/04/12 11.12, David Baelde wrote: >> Hi Haris, >> >> Yes, liquidsoap supports video. It is not used very much, essentially >> because the model for video is the same as for audio, meaning the we >> decode all inputs and reencode before output. While this is generally >> unnoticed for audio, it can be quite costly for video. However, if you >> want to mix video, you can't really expect anything else than >> decoding+mixing+encoding, so this shouldn't come as a surprise. > I am fully aware of this. > Intention is to use source video in very high quality as to avoid such > quality loss. >> >> The other reason why there aren't so many examples around is that they >> are not so different from audio examples. Most operators are the same, >> the most notable exception being outputs. If you have a playlist of >> video files, just try output.sdl(fallible=true,playlist("file.txt")). >> You can also use add(), switch() and other common operators. > ok. I guess the effects of transitions between videos will be different > but I found the extensive list here > http://savonet.sourceforge.net/doc-svn/reference.html > correct? Yes. Most of video transitions operators have "video" in their name. >> Besides the video-static example, you can have a look at >> <http://savonet.sourceforge.net/on2_part3.html>. I have also recently >> used liquidsoap to capture video + audio and create short videos of >> talks given by students. A few months ago, I've created a quick and >> dirty video conferencing system using harbor I/O (builtin icecast) and >> webcam inputs. However, this last experiment revealed some bugs that >> have not been fully understood and fixed: while our video >> infrastructure is mature, the fact that it isn't used much means that >> several bugs are still hidden here and there... > It would help very much if could find some document about video handling > limitations. > 1. Requirments for input video format/encoding, which input formats are > supported? > 2. Possibilities for output encoding, for example, is there a support > for encoding output stream in H264/AAC via RTMP or RTSP to send out to > alternative streaming servers? Unfortunately this is all very limited for now.. We have only two formats for output and input: Theora and Dirac. Streaming can be done to an icecast server only. You can also compose videos using images and audio. We support a bunch of image formats as input. Sorry if that sounds limited.. Video streaming is quite recent in liquidsoap and it still needs improvements regarding input and output formats.. Contributions are welcomed, of course in this area.. :-) Romain |