mirror of
https://gitlab.freedesktop.org/gstreamer/gstreamer.git
synced 2024-11-20 00:31:13 +00:00
docs: merge QoS message fields
There was already a section about QoS messages that is now merged with the new information.
This commit is contained in:
Wim Taymans
parent
74ea1b5fcf
commit
7d99d0eb54
1 changed files with 49 additions and 79 deletions
|
|
@ -53,40 +53,72 @@ operations.
|
|||
QoS message
|
||||
-----------
|
||||
|
||||
Whenever QoS discards a piece of data or affects the quality of the stream, a
|
||||
message must be posted by the element that performed the QoS. We assume that
|
||||
the time gained by dropping the data outweighs the time spend in creating and
|
||||
posting the QoS message so that posting the message should not cause more
|
||||
performance problems.
|
||||
A QOS message is posted on the bus whenever an element decides to:
|
||||
|
||||
- drop a buffer because of QoS reasons
|
||||
- change its processing strategy because of QoS reasons (quality)
|
||||
|
||||
It should be expected that creating and posting the QoS message is reasonably
|
||||
fast and does not significantly contribute to the QoS problems. Options to
|
||||
disable this feature could also be presented on elements.
|
||||
|
||||
This message can be posted by a sink/src that performs synchronisation against the
|
||||
clock or it could be dropped by an upstream element that performs QoS because of
|
||||
QOS events received from a downstream element.
|
||||
clock (live) or it could be dropped by an upstream element that performs QoS
|
||||
because of QOS events received from a downstream element (!live).
|
||||
|
||||
The GST_MESSAGE_QOS contains at least the following info:
|
||||
|
||||
- live: G_TYPE_BOOLEAN:
|
||||
If the QoS message was dropped by a live element such as a sink or a live
|
||||
source. If the live property is FALSE, the QoS message was generated as a
|
||||
response to a QoS event in a non-live element.
|
||||
|
||||
- running-time, G_TYPE_UINT64:
|
||||
The running_time of the buffer that generated the QoS message.
|
||||
|
||||
- stream-time, G_TYPE_UINT64:
|
||||
The stream_time of the buffer that generated the QoS message.
|
||||
|
||||
- timestamp, G_TYPE_UINT64:
|
||||
Running_time of the data that is dropped.
|
||||
The timestamp of the buffer that generated the QoS message.
|
||||
|
||||
- duration, G_TYPE_UINT64:
|
||||
The duration of the buffer that generated the QoS message.
|
||||
|
||||
|
||||
- jitter, G_TYPE_INT64:
|
||||
The lateness of the buffer.
|
||||
The difference of the running-time against the deadline. Negative
|
||||
values mean the timestamp was on time. Positive values indicate the
|
||||
timestamp was late (and dropped) by that amount. The deadline can be
|
||||
a realtime running_time or an estimated running_time.
|
||||
|
||||
- proportion, G_TYPE_DOUBLE:
|
||||
Long term prediction of the ideal rate.
|
||||
Long term prediction of the ideal rate relative to normal rate to get
|
||||
optimal quality.
|
||||
|
||||
Optional stats:
|
||||
- quality, G_TYPE_INT:
|
||||
An element dependent integer value that specifies the current quality
|
||||
level of the element. The default maximum quality is 1000000.
|
||||
|
||||
- dropped, G_TYPE_INT64:
|
||||
The total number of dropped buffers since the element went to READY
|
||||
last. -1 if unknown.
|
||||
|
||||
- handled, G_TYPE_INT64:
|
||||
The total number of processed buffers since the element went to READY
|
||||
last. -1 if unknown.
|
||||
- format, GST_TYPE_FORMAT
|
||||
Units of the 'processed' and 'dropped' fields. Video sinks and video
|
||||
filters will use GST_FORMAT_BUFFERS (frames). Audio sinks and audio filters
|
||||
will likely use GST_FORMAT_DEFAULT (samples).
|
||||
|
||||
- processed: G_TYPE_UINT64:
|
||||
Total number of units correctly precessed since the last state change to
|
||||
READY or a flushing operation.
|
||||
|
||||
- dropped: G_TYPE_UINT64:
|
||||
Total number of units dropped since the last state change to READY or a
|
||||
flushing operation.
|
||||
|
||||
The 'running-time' and 'processed' fields can be used to estimate the average
|
||||
processing rate (framerate for video).
|
||||
|
||||
Elements might add additional fields in the message which are documents in the
|
||||
relevant elements or baseclasses.
|
||||
|
||||
|
||||
Collecting statistics
|
||||
|
|
@ -244,68 +276,6 @@ real time performance.
|
|||
- assign more CPU(s) to critical pipeline parts
|
||||
|
||||
|
||||
QoS Messages
|
||||
------------
|
||||
|
||||
A QOS message is posted on the bus whenever an element decides to:
|
||||
|
||||
- drop a buffer because of QoS reasons
|
||||
- change its processing strategy because of QoS reasons (quality)
|
||||
|
||||
It should be expected that creating and posting the QoS message is reasonably
|
||||
fast and does not significantly contribute to the QoS problems. Options to
|
||||
disable this feature could also be presented on elements.
|
||||
|
||||
The GST_MESSAGE_QOS contains at least the following info:
|
||||
|
||||
- running-time, G_TYPE_UINT64:
|
||||
The running_time of the buffer that generated the QoS message.
|
||||
|
||||
- stream-time, G_TYPE_UINT64:
|
||||
The stream_time of the buffer that generated the QoS message.
|
||||
|
||||
- timestamp, G_TYPE_UINT64:
|
||||
The timestamp of the buffer that generated the QoS message.
|
||||
|
||||
- duration, G_TYPE_UINT64:
|
||||
The duration of the buffer that generated the QoS message.
|
||||
|
||||
|
||||
- jitter, G_TYPE_INT64:
|
||||
The difference of the running-time against the deadline. Negative
|
||||
values mean the timestamp was on time. Positive values indicate the
|
||||
timestamp was late (and dropped) by that amount. The deadline can be
|
||||
a realtime running_time or an estimated running_time.
|
||||
|
||||
- proportion, G_TYPE_DOUBLE:
|
||||
Long term prediction of the ideal rate relative to normal rate to get
|
||||
optimal quality.
|
||||
|
||||
- quality, G_TYPE_INT:
|
||||
An element dependent integer value that specifies the current quality
|
||||
level of the element. The default maximum quality is 1000000.
|
||||
|
||||
|
||||
- format, GST_TYPE_FORMAT
|
||||
Units of the 'processed' and 'dropped' fields. Video sinks and video
|
||||
filters will use GST_FORMAT_BUFFERS (frames). Audio sinks and audio filters
|
||||
will likely use GST_FORMAT_DEFAULT (samples).
|
||||
|
||||
- processed: G_TYPE_UINT64:
|
||||
Total number of units correctly precessed since the last state change to
|
||||
READY or a flushing operation.
|
||||
|
||||
- dropped: G_TYPE_UINT64:
|
||||
Total number of units dropped since the last state change to READY or a
|
||||
flushing operation.
|
||||
|
||||
The 'running-time' and 'processed' fields can be used to estimate the average
|
||||
processing rate (framerate for video).
|
||||
|
||||
Elements might add additional fields in the message which are documents in the
|
||||
relevant elements or baseclasses.
|
||||
|
||||
|
||||
QoS implementations
|
||||
-------------------
|
||||
|
||||
|
|
|
|||
Loading…
Reference in a new issue