mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
synced 2025-01-19 05:45:58 +00:00
design: framestep: formatting and markup fixes
- Drop manual padding of figures - Add missing markup - Make subsections over the use cases and trim their heading not to be redundant - Minor grammar fixes
This commit is contained in:
Reynaldo H. Verdejo Pinochet
parent
8c0afd11c2
commit
8ee70333cf
1 changed files with 34 additions and 37 deletions
|
|
@ -32,16 +32,15 @@ short segments of data in PLAYING.
|
|||
|
||||
## Use Cases
|
||||
|
||||
* frame stepping in video only pipeline in PAUSED
|
||||
### video only pipeline in PAUSED
|
||||
|
||||
```
|
||||
.-----. .-------. .------. .-------.
|
||||
| src | | demux | .-----. | vdec | | vsink |
|
||||
| src->sink src1->|queue|->sink src->sink |
|
||||
'-----' '-------' '-----' '------' '-------'
|
||||
``````
|
||||
.-----. .-------. .------. .-------.
|
||||
| src | | demux | .-----. | vdec | | vsink |
|
||||
| src->sink src1->|queue|->sink src->sink |
|
||||
'-----' '-------' '-----' '------' '-------'
|
||||
```
|
||||
|
||||
*
|
||||
- app sets the pipeline to PAUSED to block on the preroll picture
|
||||
|
||||
- app seeks to required position in the stream. This can be done
|
||||
|
|
@ -55,20 +54,19 @@ short segments of data in PLAYING.
|
|||
- sink posts `STEP_DONE` with amount of frames stepped and
|
||||
corresponding time interval.
|
||||
|
||||
* frame stepping in audio/video pipeline in PAUSED
|
||||
### audio/video pipeline in PAUSED
|
||||
|
||||
```
|
||||
.-----. .-------. .------. .-------.
|
||||
| src | | demux | .-----. | vdec | | vsink |
|
||||
| src->sink src1->|queue|->sink src->sink |
|
||||
'-----' | | '-----' '------' '-------'
|
||||
| | .------. .-------.
|
||||
| | .-----. | adec | | asink |
|
||||
| src2->|queue|->sink src->sink |
|
||||
'-------' '-----' '------' '-------'
|
||||
.-----. .-------. .------. .-------.
|
||||
| src | | demux | .-----. | vdec | | vsink |
|
||||
| src->sink src1->|queue|->sink src->sink |
|
||||
'-----' | | '-----' '------' '-------'
|
||||
| | .------. .-------.
|
||||
| | .-----. | adec | | asink |
|
||||
| src2->|queue|->sink src->sink |
|
||||
'-------' '-----' '------' '-------'
|
||||
```
|
||||
|
||||
*
|
||||
- app sets the pipeline to PAUSED to block on the preroll picture
|
||||
|
||||
- app seeks to required position in the stream. This can be done
|
||||
|
|
@ -88,7 +86,7 @@ short segments of data in PLAYING.
|
|||
there needs to be enough queueing in the pipeline to compensate
|
||||
for the accumulated audio.
|
||||
|
||||
- frame stepping in audio/video pipeline in PLAYING
|
||||
### audio/video pipeline in PLAYING
|
||||
|
||||
- app sets the pipeline to PAUSED to block on the preroll picture
|
||||
|
||||
|
|
@ -116,23 +114,22 @@ short segments of data in PLAYING.
|
|||
A new `GST_EVENT_STEP` event is introduced to start the step operation.
|
||||
The step event is created with the following fields in the structure:
|
||||
|
||||
* **`format`** GST_TYPE_FORMAT: The format of the step units
|
||||
* **`format`** `GST_TYPE_FORMAT`: The format of the step units
|
||||
|
||||
* **`amount`** G_TYPE_UINT64: The amount of units to step. A 0 amount
|
||||
* **`amount`** `G_TYPE_UINT64`: The amount of units to step. A 0 amount
|
||||
immediately completes and can be used to cancel the current step and resume
|
||||
normal non-stepping behaviour to the end of the segment. A -1 amount steps
|
||||
until the end of the segment.
|
||||
|
||||
* **`rate`** G_TYPE_DOUBLE: The rate at which the frames should be stepped in
|
||||
* **`rate`** `G_TYPE_DOUBLE`: The rate at which the frames should be stepped in
|
||||
PLAYING mode. 1.0 is the normal playback speed and direction of the segment,
|
||||
2.0 is double speed. A speed of 0.0 is not allowed. When performing a flushing
|
||||
step, the speed is not relevant. Note that we don't allow negative rates here,
|
||||
use a seek with a negative rate first to reverse the playback direction.
|
||||
|
||||
* **`flush`** G_TYPE_BOOLEAN: when flushing is TRUE, the step is performed
|
||||
* **`flush`** `G_TYPE_BOOLEAN`: when flushing is TRUE, the step is performed
|
||||
immediately:
|
||||
|
||||
*
|
||||
- In the PAUSED state the pipeline loses the PAUSED state, the
|
||||
requested amount of data is skipped and the pipeline prerolls again
|
||||
when a non-intermediate step completes. When the pipeline was
|
||||
|
|
@ -156,14 +153,14 @@ immediately:
|
|||
operation, the step operation will be performed from the position of
|
||||
the last PAUSED state.
|
||||
|
||||
* **`intermediate`** G_TYPE_BOOLEAN: Signal that this step operation is an
|
||||
* **`intermediate`** `G_TYPE_BOOLEAN`: Signal that this step operation is an
|
||||
intermediate step, part of a series of step operations. It is mostly
|
||||
interesting for stepping in the PAUSED state because the sink will only perform
|
||||
a preroll after a non-intermediate step operation completes. Intermediate steps
|
||||
are useful to flush out data from other sinks in order to not cause excessive
|
||||
queueing. In the PLAYING state the intermediate flag has no visual effect. In
|
||||
all states, the intermediate flag is passed to the corresponding
|
||||
GST_MESSAGE_STEP_DONE.
|
||||
`GST_MESSAGE_STEP_DONE`.
|
||||
|
||||
The application will create a STEP event to start or stop the stepping
|
||||
operation. Both stepping in PAUSED and PLAYING can be performed by means
|
||||
|
|
@ -191,15 +188,15 @@ fields.
|
|||
|
||||
* **`active`**: If the step was queued or activated.
|
||||
|
||||
* **`format`** GST_TYPE_FORMAT: The format of the step units that queued/activated.
|
||||
* **`format`** `GST_TYPE_FORMAT`: The format of the step units that queued/activated.
|
||||
|
||||
* **`amount`** G_TYPE_UINT64: The amount of units that were queued/activated.
|
||||
* **`amount`** `G_TYPE_UINT64`: The amount of units that were queued/activated.
|
||||
|
||||
* **`rate`** G_TYPE_DOUBLE: The rate and direction at which the frames were queued/activated.
|
||||
* **`rate`** `G_TYPE_DOUBLE`: The rate and direction at which the frames were queued/activated.
|
||||
|
||||
* **`flush`** G_TYPE_BOOLEAN: If the queued/activated frames will be flushed.
|
||||
* **`flush`** `G_TYPE_BOOLEAN`: If the queued/activated frames will be flushed.
|
||||
|
||||
* **`intermediate`** G_TYPE_BOOLEAN: If this is an intermediate step operation
|
||||
* **`intermediate`** `G_TYPE_BOOLEAN`: If this is an intermediate step operation
|
||||
that queued/activated.
|
||||
|
||||
The `STEP_START` message is emitted 2 times:
|
||||
|
|
@ -218,13 +215,13 @@ possible moment.
|
|||
A new `GST_MESSAGE_STEP_DONE` message is created. It contains the
|
||||
following fields:
|
||||
|
||||
* **`format`** GST_TYPE_FORMAT: The format of the step units that completed.
|
||||
* **`amount`** G_TYPE_UINT64: The amount of units that were stepped.
|
||||
* **`rate`** G_TYPE_DOUBLE: The rate and direction at which the frames were stepped.
|
||||
* **`flush`** G_TYPE_BOOLEAN: If the stepped frames were flushed.
|
||||
* **`intermediate`** G_TYPE_BOOLEAN: If this is an intermediate step operation that completed.
|
||||
* **`duration`** G_TYPE_UINT64: The total duration of the stepped units in `GST_FORMAT_TIME`.
|
||||
* **`eos`** G_TYPE_BOOLEAN: The step ended because of EOS.
|
||||
* **`format`** `GST_TYPE_FORMAT`: The format of the step units that completed.
|
||||
* **`amount`** `G_TYPE_UINT64`: The amount of units that were stepped.
|
||||
* **`rate`** `G_TYPE_DOUBLE`: The rate and direction at which the frames were stepped.
|
||||
* **`flush`** `G_TYPE_BOOLEAN`: If the stepped frames were flushed.
|
||||
* **`intermediate`** `G_TYPE_BOOLEAN`: If this is an intermediate step operation that completed.
|
||||
* **`duration`** `G_TYPE_UINT64`: The total duration of the stepped units in `GST_FORMAT_TIME`.
|
||||
* **`eos`** `G_TYPE_BOOLEAN`: The step ended because of EOS.
|
||||
|
||||
The message is emitted by the element that performs the step operation.
|
||||
The purpose is to return the duration in `GST_FORMAT_TIME` of the
|
||||
|
|
|
|||
Loading…
Reference in a new issue