[Vorbis-dev] Enhanced Podcasts with Ogg Vorbis (Chapter Marks)

[Georg Holzmann]

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<grh at mur.at>   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


-- 
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