1 |
On Mon, May 04, 2015 at 08:10:12AM +0300, Nikos Chantziaras wrote: |
2 |
> Currently, I have an ebuild for a project of mine that needs gstreamer |
3 |
> (1.x) to play videos. I have these deps: |
4 |
> |
5 |
> RDEPEND="(media-libs/gst-plugins-good:1.0 |
6 |
> media-plugins/gst-plugins-libav)" |
7 |
> |
8 |
> DEPEND="media-libs/gst-plugins-base:1.0" |
9 |
> |
10 |
> During building, some headers from plugins-base are needed and libraries |
11 |
> from that are linked directly, that's why that's in DEPEND and the |
12 |
> others in RDEPEND. |
13 |
> |
14 |
> However, if the system has no gstreamer installation at all currently, |
15 |
> then this will not install stuff like media-plugins/gst-plugins-pulse, |
16 |
> which might be needed on a PulseAudio-enabled system. |
17 |
> |
18 |
> Should I also depend on media-plugins/gst-plugins-meta in order to make |
19 |
> sure that this gets installed? |
20 |
> |
21 |
> Note that the project in question doesn't care at all about this |
22 |
> low-level stuff. PulseAudio or ALSA for example doesn't matter. All the |
23 |
> project knows about is the gstreamer API, plugins-good and plugins-base. |
24 |
> |
25 |
> Even plugins-libav is not used directly, but is a dep simply because |
26 |
> that's the only way to get gstreamer to *hopefully* play all video |
27 |
> formats correctly (assuming the user hasn't crippled libav by disabling |
28 |
> USE flags in media-video/libav.) I wouldn't know how to prevent that |
29 |
> from happening in the first place; for example, how do I make sure the |
30 |
> ebuild can request all deps in a way that makes playback of H.264 or VC8 |
31 |
> or Theora video possible. Again through plugins-meta? That lacks an h264 |
32 |
> USE flag though (but does have an "ffmpeg" USE flag which pulls |
33 |
> plugins-libav as a dep.) |
34 |
|
35 |
I would just look for an example in the tree that does something with |
36 |
gstreamer. net-im/pidgin-2.10.11 has the following in RDEPEND (which |
37 |
is included in DEPEND). For something like pidgin, where it is known |
38 |
in advance that particular codecs are needed to generally get voice |
39 |
chat support with popular IM networks, it makes sense to force at |
40 |
least support for those codecs. |
41 |
|
42 |
gstreamer? ( =media-libs/gstreamer-0.10* |
43 |
=media-libs/gst-plugins-good-0.10* |
44 |
net-libs/farstream:0.1 |
45 |
media-plugins/gst-plugins-meta:0.10 |
46 |
media-plugins/gst-plugins-gconf:0.10 ) |
47 |
|
48 |
Mozillaish ebuilds (at least FireFox and SeaMonkey, through |
49 |
mozconfig-v5.36.eclass) have in RDEPEND (which is fully included into |
50 |
DEPEND). It looks like they force the libav plugin, probably it gets |
51 |
support for the popular <video/>/<audio/> stuff through that? |
52 |
|
53 |
gstreamer? ( |
54 |
>=media-libs/gstreamer-1.2.3:1.0 |
55 |
>=media-libs/gst-plugins-base-1.2.3:1.0 |
56 |
>=media-libs/gst-plugins-good-1.2.3:1.0 |
57 |
>=media-plugins/gst-plugins-libav-1.1.0_pre20130128-r1:1.0 |
58 |
) |
59 |
|
60 |
If your project can only be useful to users if libav and plugins-good |
61 |
is present, then the in-tree precedents I found suggest you should |
62 |
just go ahead and depend on the codecs. I do like how you are doing |
63 |
better than the tree by only putting the codecs in RDEPEND, I think in |
64 |
rare cases that might give portage the wiggle-room it needs to handle |
65 |
dependencies during world updates, though I’m not sure. It’s being |
66 |
“more correct” and informative, at least ;-). However, be sure that |
67 |
you at least have gst-plugins-base in RDEPEND—even though it is |
68 |
implicitly there through an indirect dependency through |
69 |
gst-plugins-good and gst-plugins-libav, your project *does* directly |
70 |
use gst-plugins-base and should inform portage that it needs to be |
71 |
kept installed. |
72 |
|
73 |
However, if your project could conceivably be useful with a more |
74 |
minimal set of gstreamer codecs, it might be nice to give the user |
75 |
more power by putting the default set of codecs behind a |
76 |
default-enabled useflag. Something like: |
77 |
|
78 |
IUSE="+gstreamer-codecs" |
79 |
|
80 |
COMMON_DEPEND="media-libs/gst-plugins-base:1.0" |
81 |
RDEPEND="${COMMON_DEPEND} |
82 |
gstreamer-codecs? ( media-libs/gst-plugins-good:1.0 |
83 |
media-plugins/gst-plugins-libav )" |
84 |
DEPEND="${COMMON_DEPEND}" |
85 |
|
86 |
This would enable power users to choose what gstreamer codecs to |
87 |
build, especially if they are targeting something like an embedded |
88 |
system. |
89 |
|
90 |
Hopefully I said something wrong that will trigger someone else to |
91 |
provide actual useful information ;-). |
92 |
|
93 |
-- |
94 |
binki |
95 |
|
96 |
Look out for missing or extraneous apostrophes! |