Re: Enhanced Podcasts with Ogg Vorbis (Chapter Marks)
Georg Holzmann <[email protected]> Thu, 12 Apr 2012 08:44:26 +0200
| Newsgroups | gmane.comp.multimedia.ogg.vorbis.devel |
|---|---|
| Message-ID | <[email protected]> |
Hallo! >> That's great ;) >> Should it also be allowed to have multiple URLs per chapter? >> (Just by using the same CHAPTERxxxURL key multiple times) > > It doesn't really matter if we specify that or not. What matters is whether an app supports multiple links. If it doesn't then a file with multiple links in a chaptermay just mean that the first ones are replaced and never accessible. What do actual players do? You are right. In the MP4-podcasting world they use one link all the time (which is shown by players like instacast), but I don't know why ... >>> Thus, this would work: >>> CHAPTERxxxBLOCKPICTURE=blahblah >>> [...] > > Well I won't add anything until we have an answer. OK - fine! Have a nice day! LG Georg > > Cheers, > Silvia. > >> Thanks for your answer! >> LG >> Georg >> >>> >>> Cheers, >>> Silvia. >>> >>> >>> On Mon, Apr 2, 2012 at 10:31 PM, Georg Holzmann<[email protected]> wrote: >>>> Hallo Sivlia, Martin! >>>> >>>> >>>>> Somebody (perhaps Georg) suggested this a >>>>> few weeks ago at: >>>>> https://wiki.xiph.org/Talk:Chapter_Extension >>>> >>>> No, this wasn't me - but nice to see that others are interested too ... ;) >>>> >>>> >>>>> I think that would turn chapters into a really confused content track. >>>>> Think about it: chapters are there to provide navigation pointers to >>>>> people that come to the video. Now you're attaching outgoing pointers >>>>> to the incoming anchors. That's a very separate type of content and >>>>> requires rendering of the outgoing pointers and enable user >>>>> interaction. In particular if you want to enable more than one >>>>> hyperlink, how is that supposed to be rendered? >>>> >>>> >>>> We just get this feature request and are implementing this ATM for MP4 and >>>> MP3 audio - and thought it would be nice to have in Vorbis too ... >>>> In MP4 you have a separate track, in MP3 (ID3) this is directly attached to >>>> the chapters [1]. >>>> >>>> Podcast authoring software, like Hindeburg (see [2] how they create >>>> chapters) or I thing also Garageband, allows you to set a link and a picture >>>> for a chapter, and clients also display them (e.g. players on the >>>> "i-devices" or the popular instacast [3]). >>>> >>>> >>>>> Instead, I would suggest to create actual content tracks, i.e. tracks >>>>> that have text or markup in them and have been built to be displayed. >>>>> The way that we recommend doing this are Kate tracks. You can author >>>>> them as SRT or KATE files (hopefully we will also support WebVTT at >>>>> some stage). You would author cues that align with your chapter >>>>> markers if necessary, but they don't have to, because the content will >>>>> be active as you're watching the video. This is in comparison to >>>>> chapter markers which are visible *before* you start watching the >>>>> video. >>>> >>>> >>>> Yes, that would be the other possibility. >>>> >>>> However, do you know if (hardware) player have problems with ogg audio files >>>> with kate tracks? >>>> Because it would be quite trivial to add them in the VorbisComment header >>>> ... >>>> >>>> >>>> >>>>>> Yes, and the final thing would be images for chapters ;) (or at some >>>>>> timepoints) >>>>> >>>>> >>>>> So, this is another issue altogether. If you want chapters displayed >>>>> for navigation purposes, but augmented with sample frames for the >>>>> chapters to give a visual indication of what one may jump into when >>>>> going to the chapter, then we have to add these representative images >>>>> to the chapters. Typically, they would be frames taken from the video. >>>> >>>> >>>> Note: I am speaking about audio only files (although that might be useful >>>> for videos as well). >>>> In enhanced podcasts these images are displayed when you play the file. >>>> >>>> >>>>> Alternatively, that could be a base64 encoded image and inlined, >>>>> similar to how cover art can currently be included in VORBISCOMMENT >>>>> [1]. Maybe a field name of CHAPTER001BLOCKPICTURE for this? >>>> >>>> >>>> Yes, I also thought about this way ... >>>> However, AFAIK there are problem with some hardware players if the >>>> vorbiscomment header gets too big? >>>> And if you have multiple images, the header will be very big ... >>>> >>>> >>>>> OggSpots is not for this purpose - it was suggested as a low bandwidth >>>>> "video" codec that just shows still images at certain times, but never >>>>> got implemented. >>>>> OggKate is for caption, karaoke and similar text tracks. You could put >>>>> hyperlinks into OggKate, but I believe it would just be rendered as >>>>> text by those players that understand OggKate. So, I'm not sure it >>>>> will solve your problem. >>>> >>>> >>>> OK, thanks. I thought images are also possible with OggKate as noted here: >>>> http://wiki.xiph.org/OggKate#Images >>>> >>>> >>>> Thanks for the answers! >>>> LG >>>> Georg >>>> >>>> >>>> [1]: http://www.id3.org/id3v2-chapters-1.0 >>>> [2]: see this video on how to create chapters with links and images with >>>> hindeburg: >>>> http://www.youtube.com/watch?v=Ago1_7aLYQY&feature=plcp&context=C4f45b8eVDvjVQa1PpcFP7RTwouNwgPPcMIyFDSz86-Fh1LfinAw8%3D >>>> [3]: http://vemedio.com/products/instacast >>>> >>>> >>>> -- >>>> auphonic - automatic audio post production >>>> http://auphonic.com >>>> audio development, machine learning, open source and more >> >> >> -- >> auphonic - automatic audio post production >> http://auphonic.com >> audio development, machine learning, open source and more -- auphonic - automatic audio post production http://auphonic.com audio development, machine learning, open source and more