mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
synced 2024-11-27 12:11:13 +00:00
110 lines
No EOL
4.1 KiB
Markdown
110 lines
No EOL
4.1 KiB
Markdown
---
|
|
title: Scenarios
|
|
short-description: The GstValidate Scenario format
|
|
...
|
|
|
|
# GstValidate Scenario File Format
|
|
|
|
To be able to define a list of actions to execute on a [`GstPipeline`],
|
|
a dedicated file format is used. The name of the scenario is the name of
|
|
the file without its `.scenario` extension. The scenario file format is
|
|
based on the [`GstStructure`] serialized format which is a basic, type
|
|
aware, key value format. It takes the type of the action in the first
|
|
comma separated field, and then some key value pairs in the form
|
|
`parameter=value` separated by commas. The values type will be guessed
|
|
if not casted as in `parameter=(string)value`. You can force the type
|
|
guessing system to actually know what type you want by giving it the
|
|
right hints. For example to make sure the value is a double, you should
|
|
add a decimal (ie. `1` will be considered as a `int`, but `1.0` will be
|
|
considered as a `double` and `"1.0"` will be considered as a `string`).
|
|
|
|
For example to represent a seek action, you should add the following
|
|
line in the `.scenario` file.
|
|
|
|
seek, playback-time=10.0, start=0.0, flags=accurate+flush
|
|
|
|
The files to be used as scenario should have a `.scenario` extension and
|
|
should be placed either in
|
|
`$USER_DATA_DIR/gstreamer-1.0/validate/scenarios` ,
|
|
`$GST_DATADIR/gstreamer-1.0/validate/scenarios` or in a path defined in
|
|
the \$GST\_VALIDATE\_SCENARIOS\_PATH environment variable.
|
|
|
|
Each line in the `.scenario` file represent an action (you can also use
|
|
`\ ` at the end of a line write a single action on multiple lines).
|
|
Usually you should start you scenario with a `meta` structure
|
|
in order for the user to have more information about the
|
|
scenario. It can contain a `summary` field which is a string explaining
|
|
what the scenario does and then several info fields about the scenario.
|
|
You can find more info about it running:
|
|
|
|
gst-validate-1.0 --inspect-action-type action_type_name
|
|
|
|
So a basic scenario file that will seek three times and stop would look
|
|
like:
|
|
|
|
```
|
|
meta, summary="Seeks at 1.0 to 2.0 then at \
|
|
3.0 to 0.0 and then seeks at \
|
|
1.0 to 2.0 for 1.0 second (between 2.0 and 3.0).", \
|
|
seek=true, duration=5.0, min-media-duration=4.0
|
|
seek, playback-time=1.0, rate=1.0, start=2.0, flags=accurate+flush
|
|
seek, playback-time=3.0, rate=1.0, start=0.0, flags=accurate+flush
|
|
seek, playback-time=1.0, rate=1.0, start=2.0, stop=3.0, flags=accurate+flush
|
|
```
|
|
|
|
Many action types have been implemented to help users define their own
|
|
scenarios. For example there are:
|
|
|
|
- `seek`: Seeks into the stream.
|
|
- `play`: Set the pipeline state to `GST_STATE_PLAYING`.
|
|
- `pause`: Set the pipeline state to `GST_STATE_PAUSED`.
|
|
- `stop`: Stop the execution of the pipeline.
|
|
|
|
> **NOTE**: This action actually posts a [`GST_MESSAGE_REQUEST_STATE`]
|
|
> message requesting [`GST_STATE_NULL`] on the bus and the application
|
|
> should quit.
|
|
|
|
To get all the details about the registered action types, you can list
|
|
them all with:
|
|
|
|
```
|
|
gst-validate-1.0 --inspect-action-type
|
|
```
|
|
|
|
and to include transcoding specific action types:
|
|
|
|
```
|
|
gst-validate-transcoding-1.0 --inspect-action-type
|
|
```
|
|
|
|
Many scenarios are distributed with `gst-validate`, you can list them
|
|
all using:
|
|
|
|
```
|
|
gst-validate-1.0 --list-scenarios
|
|
```
|
|
|
|
You can find more information about the scenario implementation and
|
|
action types in the [`GstValidateScenario` section].
|
|
|
|
[`GstPipeline`]: GstPipeline
|
|
[`GstStructure`]: GstStructure
|
|
[`GST_MESSAGE_REQUEST_STATE`]: GST_MESSAGE_REQUEST_STATE
|
|
[`GST_STATE_NULL`]: GST_STATE_NULL
|
|
[`GstValidateScenario` section]: GstValidateScenario
|
|
|
|
## Default variables
|
|
|
|
Any action can use the default variables:
|
|
|
|
- `$(position)`: The current position in the pipeline as reported by
|
|
[gst_element_query_position()](gst_element_query_position)
|
|
- `$(duration)`: The current duration of the pipeline as reported by
|
|
[gst_element_query_duration()](gst_element_query_duration)
|
|
- `$(TMPDIR)`: The default temporary directory as returned by `g_get_tmp_dir`.
|
|
- `$(SCENARIO_PATH)`: The path of the running scenario.
|
|
- `$(SCENARIO_DIR)`: The directory the running scenario is in.
|
|
- `$(SCENARIO_NAME)`: The name the running scenario
|
|
|
|
|
|
It is also possible to set variables in scenario with the `set-vars` action. |