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docs/random/draft-missing-plugins.txt: More small fixes.

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Original commit message from CVS:
* docs/random/draft-missing-plugins.txt:
More small fixes.
This commit is contained in:
Christian Schaller 2006-11-08 02:04:52 +00:00
parent 32e77c38a9
commit 309e76f436
3 changed files with 99 additions and 84 deletions
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5
ChangeLog
View file

@ -1,3 +1,8 @@
2006-11-08 Christian F.K. Schaller <set EMAIL_ADDRESS environment variable>
* docs/random/draft-missing-plugins.txt:
More small fixes.
2006-11-07 Tim-Philipp Müller <tim at centricular dot net>
* tests/examples/typefind/typefind.c: (type_found), (main):

89
docs/design/draft-missing-plugins.txt
View file

@ -5,7 +5,7 @@ We only discuss playback pipelines for now.
A three step process:
1) gstreamer level
1) GStreamer level
- a new GstMessage type to report missing plugins:
@ -15,6 +15,8 @@ A three step process:
name: (string) { ANY } ex: "MMS protocol handler",..
=====> FIXME: really add a message type? Why not an element message? <=====
--- The reason for not adding a core message type is that the autopluggers
--- will post the element and the core is not intersted in this at all.
- missing uri handler
@ -31,7 +33,7 @@ A three step process:
- missing typefind function
We don't recognize the type of the file, this should normally not happen
because all the typefinders are in the basic gstreamer installation.
because all the typefinders are in the basic GStreamer installation.
There is not much useful information we can give about how to resolve this
issue. It is possible to use the first N bytes of the data to determine the
type (and needed plugin) on the server. We don't explore this option in this
@ -67,10 +69,49 @@ A three step process:
and the friendly name optionally set to a description of the element's
functionality in the decoding pipeline.
Except for reported the missing plugins, no further policy is enforced at the
gstreamer level. It is up to the application to decide whether a missing
Except for reporting the missing plugins, no further policy is enforced at the
GStreamer level. It is up to the application to decide whether a missing
plugin constitutes a problem or not.
2) application level
The application's job is to listen for the MISSING_PLUGIN messages and to
decide on a policy to handle them. Following cases exist:
- partially missing plugins
The application will be able to complete a state change to PAUSED but there
will be a MISSING_PLUGIN message on the GstBus.
This means that it will be possible to play back part of the media file but not
all of it.
For example: suppose we have an .avi file with mp3 audio and divx video. If we
have the mp3 audio decoder but not the divx video decoder, it will be possible
to play only the audio part but not the video part. For an audio playback
application, this is not a problem but a video player might want to decide on:
- require the use to install the additionally required plugins.
- inform the user that only the audio will be played back
- ask the user if it should download the additional codec or only play the
audio part.
- ...
- completely unplayable stream
The application will receive an ERROR message from GStreamer informing it that
playback stopped (before it could reach PAUSED). This happens because none of
the streams is connected to a decoder.
The application can then see that there are a set of MISSING_PLUGIN messages on
the GstBus and can decide to trigger the download procedure. It does that
by calling gst_install_missing_plugins() which is documented above, passing
the MISSING_PLUGIN messages collected.
3) Plugin download stage
In addition, a thin callback API will be added to GStreamer to initiate
plugin download and receive feedback about whether the plugin download
succeeded (in full or partially) or failed.
@ -78,7 +119,7 @@ A three step process:
struct GstMissingPluginHandler {
/* This function must be blocking; the function is implemented by an
* external library (chosen by the application) */
gboolean (*install_plugins) (const gchar ** missing_ids, GError ** error);
gboolean (*install_plugins) (const gchar ** missing_ids, GError ** error, gpointer handler_data);
/*< private >*/
gpointer padding[GST_PADDING];
@ -95,6 +136,7 @@ A three step process:
* of locking or marshalling the result back into the main thread in a
* thread-safe manner */
gboolean gst_install_missing_plugins (const GstMissingPluginHandler * handler,
gpointer handler_data,
GList * messages,
GstMissingPluginInstallResultFunc result_callback,
gpointer result_callback_data,
@ -141,40 +183,3 @@ A three step process:
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
caps in a unified and consistent way.
2) application level
The application's job is to listen for the MISSING_PLUGIN messages and to
decide on a policy to handle them.
- partially missing plugins
The application will be able to complete a state change to PAUSED but there
will be a MISSING_PLUGIN message on the GstBus.
This means that it will be possible to play back part of the media file but not
all of it.
For example: suppose we have an .avi file with mp3 audio and divx video. If we
have the mp3 audio decoder but not the divx video decoder, it will be possible
to play only the audio part but not the video part. For an audio playback
application, this is not a problem but a video player might want to decide on:
- require the use to install the additionally required plugins.
- inform the user that only the audio will be played back
- ask the user if it should download the additional codec or only play the
audio part.
- ...
- completely unplayable stream
The application will receive an ERROR message from gstreamer informing it that
playback stopped (before it could reach PAUSED).
The application can then see that there are a set of MISSING_PLUGIN messages on
the GstBus and can decide to trigger the download procedure. It does that
by calling gst_install_missing_plugins() which is documented above, passing
the MISSING_PLUGIN messages collected.

89
docs/random/draft-missing-plugins.txt
View file

@ -5,7 +5,7 @@ We only discuss playback pipelines for now.
A three step process:
1) gstreamer level
1) GStreamer level
- a new GstMessage type to report missing plugins:
@ -15,6 +15,8 @@ A three step process:
name: (string) { ANY } ex: "MMS protocol handler",..
=====> FIXME: really add a message type? Why not an element message? <=====
--- The reason for not adding a core message type is that the autopluggers
--- will post the element and the core is not intersted in this at all.
- missing uri handler
@ -31,7 +33,7 @@ A three step process:
- missing typefind function
We don't recognize the type of the file, this should normally not happen
because all the typefinders are in the basic gstreamer installation.
because all the typefinders are in the basic GStreamer installation.
There is not much useful information we can give about how to resolve this
issue. It is possible to use the first N bytes of the data to determine the
type (and needed plugin) on the server. We don't explore this option in this
@ -67,10 +69,49 @@ A three step process:
and the friendly name optionally set to a description of the element's
functionality in the decoding pipeline.
Except for reported the missing plugins, no further policy is enforced at the
gstreamer level. It is up to the application to decide whether a missing
Except for reporting the missing plugins, no further policy is enforced at the
GStreamer level. It is up to the application to decide whether a missing
plugin constitutes a problem or not.
2) application level
The application's job is to listen for the MISSING_PLUGIN messages and to
decide on a policy to handle them. Following cases exist:
- partially missing plugins
The application will be able to complete a state change to PAUSED but there
will be a MISSING_PLUGIN message on the GstBus.
This means that it will be possible to play back part of the media file but not
all of it.
For example: suppose we have an .avi file with mp3 audio and divx video. If we
have the mp3 audio decoder but not the divx video decoder, it will be possible
to play only the audio part but not the video part. For an audio playback
application, this is not a problem but a video player might want to decide on:
- require the use to install the additionally required plugins.
- inform the user that only the audio will be played back
- ask the user if it should download the additional codec or only play the
audio part.
- ...
- completely unplayable stream
The application will receive an ERROR message from GStreamer informing it that
playback stopped (before it could reach PAUSED). This happens because none of
the streams is connected to a decoder.
The application can then see that there are a set of MISSING_PLUGIN messages on
the GstBus and can decide to trigger the download procedure. It does that
by calling gst_install_missing_plugins() which is documented above, passing
the MISSING_PLUGIN messages collected.
3) Plugin download stage
In addition, a thin callback API will be added to GStreamer to initiate
plugin download and receive feedback about whether the plugin download
succeeded (in full or partially) or failed.
@ -78,7 +119,7 @@ A three step process:
struct GstMissingPluginHandler {
/* This function must be blocking; the function is implemented by an
* external library (chosen by the application) */
gboolean (*install_plugins) (const gchar ** missing_ids, GError ** error);
gboolean (*install_plugins) (const gchar ** missing_ids, GError ** error, gpointer handler_data);
/*< private >*/
gpointer padding[GST_PADDING];
@ -95,6 +136,7 @@ A three step process:
* of locking or marshalling the result back into the main thread in a
* thread-safe manner */
gboolean gst_install_missing_plugins (const GstMissingPluginHandler * handler,
gpointer handler_data,
GList * messages,
GstMissingPluginInstallResultFunc result_callback,
gpointer result_callback_data,
@ -141,40 +183,3 @@ A three step process:
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
caps in a unified and consistent way.
2) application level
The application's job is to listen for the MISSING_PLUGIN messages and to
decide on a policy to handle them.
- partially missing plugins
The application will be able to complete a state change to PAUSED but there
will be a MISSING_PLUGIN message on the GstBus.
This means that it will be possible to play back part of the media file but not
all of it.
For example: suppose we have an .avi file with mp3 audio and divx video. If we
have the mp3 audio decoder but not the divx video decoder, it will be possible
to play only the audio part but not the video part. For an audio playback
application, this is not a problem but a video player might want to decide on:
- require the use to install the additionally required plugins.
- inform the user that only the audio will be played back
- ask the user if it should download the additional codec or only play the
audio part.
- ...
- completely unplayable stream
The application will receive an ERROR message from gstreamer informing it that
playback stopped (before it could reach PAUSED).
The application can then see that there are a set of MISSING_PLUGIN messages on
the GstBus and can decide to trigger the download procedure. It does that
by calling gst_install_missing_plugins() which is documented above, passing
the MISSING_PLUGIN messages collected.