mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
synced 2024-11-26 19:51:11 +00:00
docs/random/draft-missing-plugins.txt: Some additions: mention new API that is supposed to be used at the various sta...
Original commit message from CVS: * docs/random/draft-missing-plugins.txt: Some additions: mention new API that is supposed to be used at the various stages; short blob about new gst-inspect introspection option; mention potential future problem with plugins that have a dynamic list of elements (such as ladspa, pitfdll, libvisual).
This commit is contained in:
Tim-Philipp Müller
parent
26b38870f9
commit
297db8e249
3 changed files with 126 additions and 20 deletions
|
|
@ -1,3 +1,11 @@
|
|||
2007-01-11 Tim-Philipp Müller <tim at centricular dot net>
|
||||
|
||||
* docs/random/draft-missing-plugins.txt:
|
||||
Some additions: mention new API that is supposed to be used at the
|
||||
various stages; short blob about new gst-inspect introspection
|
||||
option; mention potential future problem with plugins that have
|
||||
a dynamic list of elements (such as ladspa, pitfdll, libvisual).
|
||||
|
||||
2007-01-11 Tim-Philipp Müller <tim at centricular dot net>
|
||||
|
||||
* tools/gst-inspect.c:
|
||||
|
|
|
|||
|
|
@ -1,6 +1,9 @@
|
|||
What to do when a plugin is missing
|
||||
===================================
|
||||
|
||||
The mechanism and API described in this document requires GStreamer core and
|
||||
gst-plugins-base versions >= 0.10.12.
|
||||
|
||||
We only discuss playback pipelines for now.
|
||||
|
||||
A three step process:
|
||||
|
|
@ -111,6 +114,9 @@ A three step process:
|
|||
messages on the GstBus and can decide to trigger the download procedure. It
|
||||
does that as described in the following section.
|
||||
|
||||
"missing-plugin" element messages can be identified using the function
|
||||
gst_is_missing_plugin_message().
|
||||
|
||||
|
||||
3) Plugin download stage
|
||||
|
||||
|
|
@ -119,14 +125,17 @@ A three step process:
|
|||
- made a decision that additional plugins should be installed
|
||||
|
||||
It will call a GStreamer utility function to convert each "missing-plugin"
|
||||
message into an identifier string describing the missing capability.
|
||||
message into an identifier string describing the missing capability. This is
|
||||
done using the function gst_missing_plugin_message_get_installer_detail().
|
||||
|
||||
The application will then pass these strings to an external libgimmecodec
|
||||
to initiate the download. Error handling and progress reporting etc. will
|
||||
all be handled using libgimmecodec's API.
|
||||
The application will then pass these strings to the external libgimme-codec
|
||||
library [0] to initiate the download. Error handling and progress reporting
|
||||
etc. will all be handled using libgimmecodec's API.
|
||||
|
||||
When new plugins have been installed, the application will have to initiate
|
||||
a re-scan of the GStreamer plugin registry.
|
||||
a re-scan of the GStreamer plugin registry using gst_update_registry().
|
||||
|
||||
[0] http://desrt.mcmaster.ca/code/libgimme-codec/
|
||||
|
||||
|
||||
4) Format of the (UTF-8) string ID passed to the external installer system
|
||||
|
|
@ -174,10 +183,50 @@ A three step process:
|
|||
separated by '|' symbols and either ignore them, warn the user, or error
|
||||
out when encountering them.
|
||||
|
||||
The human-readable description string will come from a new utility
|
||||
library that yet to be added to gst-plugins-base and which can then also
|
||||
be used by demuxers to find out the codec names for taglists from given
|
||||
The human-readable description string is provided by the libgstbaseutils
|
||||
library that can be found in gst-plugins-base versions >= 0.10.12 and can
|
||||
also be used by demuxers to find out the codec names for taglists from given
|
||||
caps in a unified and consistent way.
|
||||
|
||||
There will also be API for applications to create these detail strings from
|
||||
a given missing-plugin message.
|
||||
Applications can create these detail strings using the function
|
||||
gst_missing_plugin_message_get_installer_detail() on a given missing-plugin
|
||||
message.
|
||||
|
||||
|
||||
5) Using missing-plugin messages for error reporting:
|
||||
|
||||
Missing-plugin messages are also useful for error reporting purposes, either
|
||||
in the case where the application does not support libgimme-codec, or the
|
||||
external installer is not available or not able to install the required
|
||||
plugins.
|
||||
|
||||
When creating error messages, applications may use the function
|
||||
gst_missing_plugin_message_get_description() to obtain a possibly translated
|
||||
description from each missing-plugin message (e.g. "Matroska demuxer" or
|
||||
"Theora video depayloader"). This can be used to report to the user exactly
|
||||
what it is that is missing.
|
||||
|
||||
|
||||
6) Notes for packagers
|
||||
|
||||
- An easy way to introspect plugin .so files is:
|
||||
|
||||
$ gst-inspect --print-plugin-auto-install-info /path/to/libgstfoo.so
|
||||
|
||||
The output will be something like:
|
||||
|
||||
decoder-audio/x-vorbis
|
||||
element-vorbisdec
|
||||
element-vorbisenc
|
||||
element-vorbisparse
|
||||
element-vorbistag
|
||||
encoder-audio/x-vorbis
|
||||
|
||||
- when introspecting, keep in mind that there are GStreamer plugins that
|
||||
in turn load external plugins. Examples of these are pitfdll, ladspa, or
|
||||
the GStreamer libvisual plugin. Those plugins will only announce elements
|
||||
for the currently installed external plugins at the time of introspection!
|
||||
With the exception of pitfdll, this is not really relevant to the playback
|
||||
case, but may become an issue in future when applications like buzztard,
|
||||
jokosher or pitivi start requestion elements by name, for example ladspa
|
||||
effect elements or so.
|
||||
|
|
|
|||
|
|
@ -1,6 +1,9 @@
|
|||
What to do when a plugin is missing
|
||||
===================================
|
||||
|
||||
The mechanism and API described in this document requires GStreamer core and
|
||||
gst-plugins-base versions >= 0.10.12.
|
||||
|
||||
We only discuss playback pipelines for now.
|
||||
|
||||
A three step process:
|
||||
|
|
@ -111,6 +114,9 @@ A three step process:
|
|||
messages on the GstBus and can decide to trigger the download procedure. It
|
||||
does that as described in the following section.
|
||||
|
||||
"missing-plugin" element messages can be identified using the function
|
||||
gst_is_missing_plugin_message().
|
||||
|
||||
|
||||
3) Plugin download stage
|
||||
|
||||
|
|
@ -119,14 +125,17 @@ A three step process:
|
|||
- made a decision that additional plugins should be installed
|
||||
|
||||
It will call a GStreamer utility function to convert each "missing-plugin"
|
||||
message into an identifier string describing the missing capability.
|
||||
message into an identifier string describing the missing capability. This is
|
||||
done using the function gst_missing_plugin_message_get_installer_detail().
|
||||
|
||||
The application will then pass these strings to an external libgimmecodec
|
||||
to initiate the download. Error handling and progress reporting etc. will
|
||||
all be handled using libgimmecodec's API.
|
||||
The application will then pass these strings to the external libgimme-codec
|
||||
library [0] to initiate the download. Error handling and progress reporting
|
||||
etc. will all be handled using libgimmecodec's API.
|
||||
|
||||
When new plugins have been installed, the application will have to initiate
|
||||
a re-scan of the GStreamer plugin registry.
|
||||
a re-scan of the GStreamer plugin registry using gst_update_registry().
|
||||
|
||||
[0] http://desrt.mcmaster.ca/code/libgimme-codec/
|
||||
|
||||
|
||||
4) Format of the (UTF-8) string ID passed to the external installer system
|
||||
|
|
@ -174,10 +183,50 @@ A three step process:
|
|||
separated by '|' symbols and either ignore them, warn the user, or error
|
||||
out when encountering them.
|
||||
|
||||
The human-readable description string will come from a new utility
|
||||
library that yet to be added to gst-plugins-base and which can then also
|
||||
be used by demuxers to find out the codec names for taglists from given
|
||||
The human-readable description string is provided by the libgstbaseutils
|
||||
library that can be found in gst-plugins-base versions >= 0.10.12 and can
|
||||
also be used by demuxers to find out the codec names for taglists from given
|
||||
caps in a unified and consistent way.
|
||||
|
||||
There will also be API for applications to create these detail strings from
|
||||
a given missing-plugin message.
|
||||
Applications can create these detail strings using the function
|
||||
gst_missing_plugin_message_get_installer_detail() on a given missing-plugin
|
||||
message.
|
||||
|
||||
|
||||
5) Using missing-plugin messages for error reporting:
|
||||
|
||||
Missing-plugin messages are also useful for error reporting purposes, either
|
||||
in the case where the application does not support libgimme-codec, or the
|
||||
external installer is not available or not able to install the required
|
||||
plugins.
|
||||
|
||||
When creating error messages, applications may use the function
|
||||
gst_missing_plugin_message_get_description() to obtain a possibly translated
|
||||
description from each missing-plugin message (e.g. "Matroska demuxer" or
|
||||
"Theora video depayloader"). This can be used to report to the user exactly
|
||||
what it is that is missing.
|
||||
|
||||
|
||||
6) Notes for packagers
|
||||
|
||||
- An easy way to introspect plugin .so files is:
|
||||
|
||||
$ gst-inspect --print-plugin-auto-install-info /path/to/libgstfoo.so
|
||||
|
||||
The output will be something like:
|
||||
|
||||
decoder-audio/x-vorbis
|
||||
element-vorbisdec
|
||||
element-vorbisenc
|
||||
element-vorbisparse
|
||||
element-vorbistag
|
||||
encoder-audio/x-vorbis
|
||||
|
||||
- when introspecting, keep in mind that there are GStreamer plugins that
|
||||
in turn load external plugins. Examples of these are pitfdll, ladspa, or
|
||||
the GStreamer libvisual plugin. Those plugins will only announce elements
|
||||
for the currently installed external plugins at the time of introspection!
|
||||
With the exception of pitfdll, this is not really relevant to the playback
|
||||
case, but may become an issue in future when applications like buzztard,
|
||||
jokosher or pitivi start requestion elements by name, for example ladspa
|
||||
effect elements or so.
|
||||
|
|
|
|||
Loading…
Reference in a new issue