[linux-dvb] [ANNOUNCE] DVB API improvements

Zaheer Merali zaheermerali at gmail.com
Fri Sep 26 18:35:53 CEST 2008

On Tue, Sep 23, 2008 at 10:16 PM, Mauro Carvalho Chehab
<mchehab at infradead.org> wrote:
> After years of discussions, several patch series and two different proposed
> approaches, LinuxTV developers finally decided that S2API is the better
> technical proposal and should be accepted as the way to allow supporting newer
> DTV standards, starting with DVB-S2.
> As previously announced at http://linuxtv.org/news.php?entry=2008-09-19.mchehab,
> a representative group of active developers at LinuxTV community attended the
> first V4L/DVB Summit, that started with the V4L/DVB miniconf at Linux
> Plumbers/2008. Several other additional formal (BOF's) and informal meetings
> happened there, in the benefit of the improvement of the development of
> multimedia drivers and core.
> During the miniconf, both Multiproto API (proposed by Manu) and S2API (proposed
> by Steven), were presented. A technical discussion was made during the DVB BOF
> session in order to compare the two proposals and check for the
> need/convenience of other core internal changes to draw an evolution timeline
> for DVB.
> The DVB BOF had the presence of the following LinuxTV members:
>        Douglas Schilling Landgraf
>        Hans Verkuil
>        Mauro Carvalho Chehab
>        Michael Krufky
>        Patrick Boettcher
>        Steven Toth
>        Thierry Merle
>        Manjunath Hadlii
> We had also a presence of an end-user listening to the BOF (Brandon Fouts).
> During the BOF, the LinuxTV members carefully analyzed the pros and cons for
> both proposals. At the end, all people present there agreed that S2API is
> technically more reliable in time than Multiproto proposal. So it was decided
> that S2API will be merged upstream.
> The main arguments in favor of S2API over Multiproto are:
>        - Future proof – the proposal for S2API is more flexible, easily
>          allowing the addition of newer features and new standard support;
>        - Simplicity – S2API patches are very simple, while Multiproto
>          presented a very complex series of changes. Simpler approaches
>          reduces the time for maintaining the source code;
>        - Capability of allowing improvements even on the existing standards,
>          like allowing diversity control that starts to appear on newer DVB
>          devices.
> Some improvements were proposed by the LinuxTV developers, in order to improve
> the S2API, including:
>        - Adding an API command for querying DVB version, to allow an easier
>          detection by userspace applications;
>        - Name the DVB API with S2API as DVB version 5;
>        - Update DVB API documentation to reflect the API changes;
>        - Remove from DVB API the unused API ioctls, to match the API with the
>          existing implementations.
> The author of S2API got the task of adding those suggestions at the proposed
> standard and send a pull request to the subsystem maintainer, together with
> patches for his drivers that use the newer API.
> It was also discussed that some of the internal Multiproto API changes may be
> needed in other to support some of the other existing DVB-S2 drivers that were
> developed considering Multiproto API. Internal changes can be added at any time
> without producing problems in the user API.
> The group aims to have a unified in-kernel DVB-S2 HVR4000 / TT-3200 tree (that
> also supports all of the derivative CX24116 / STB0899 known products) within 4
> weeks from the announcement, hopefully in time for kernel 2.6.28. For that, we
> would like to ask Manu to port his drivers to the new API.
> The end goal is to add proper support for all devices that would have been
> supported by multiproto and S2API alike available.
> There are already volunteers working or that have offered to work on Kaffeine
> and MythTV S2API support.
> We still need volunteers to work on dvb-apps support. If you feel that you like
> contribute, please be our guest!
> We would like to thank you all that contributed for those discussions and
> improvements to happen,
> Mauro Carvalho Chehab
> V4L/DVB Maintainer


Thank you so much for the email.I am happy that finally a decision was
made and everyone can now move forward with an API. I have had an
uncommitted patch for DVB-S2 support in GStreamer for a long time now
(using multiproto). I am happy that now I can just get DVB-S2 support
in and not have to worry about a patch bitrotting.

This list has been very painful to read over the last couple of weeks
with all the personal attacks and accusations. Please let us all
co-operate and look forward to a bright future of DVB in Linux rather
than continue negatively with the flamewar on the mailing list.


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