Caps negotiation is not as fast as it could be in 0.10. One reason is the large amount of fields in raw-caps. This page is about to rethinking the caps fields needed for raw audio and video. The content of the page is still work-in-progress. A general idea is to aggregate all enums and flags into one format field and have separate fields for continuous values. Also some fields will move from caps to buffer metadata.
Contents
todo
sync with GstBuffer in 0.11
- things that are not needed to be negotiated can go to meta-data
sync with new video caps
- add examples
- explain matching for template caps
audio
references
gstreamer
audio caps in 0.10
alsa
pulseaudio
audio/x-raw-*
Fields
name |
type |
values |
converter |
description |
sampling-rate |
uint |
> 0 |
audioresample |
data sampling rate in samples/second |
channels |
uint |
> 0 |
audioconvert |
number of audio channels |
audio/x-raw-int
Fields
name |
type |
values |
converter |
description |
format |
string |
|
audioconvert, (de)interleave |
data-layout: signed/unsigned, endianess, planar/interleaved, channel-positions |
width |
uint |
8,16,24,32 |
audioconvert |
number of bits allocated per sample |
depth |
uint |
> 0 && <=32 |
audioconvert |
number of bits used per sample |
Examples
audio/x-raw-float
Fields
name |
type |
values |
converter |
description |
format |
string |
|
audioconvert |
data layout: planar/interleaved, channel-positions |
width |
uint |
32,64 |
audioconvert |
number of bits allocated per sample |
base |
float |
* |
- |
0 db base (implicitely = 1.0 in gst-0.10) |
Examples
video
references
gstreamer
video caps in 0.10
fourcc
video/x-raw-*
Fields
name |
type |
values |
converter |
description |
width |
uint |
> 0 |
videoscale |
image width in pixels |
height |
uint |
> 0 |
videoscale |
image height in pixels |
frame-rate |
fraction |
|
videorate |
avg. framerate in frames per second |
pixel-aspect-ratio |
fraction |
|
videoscale |
width/height ration of a pixel |
views |
uint |
> 0 |
- |
number of views (2 for stereoscopic video) |
video-x-raw-rbg
Fields
name |
type |
values |
converter |
description |
format |
string |
|
colorspace |
data layout: fourcc, interlaced, view-positions |
Examples
video-x-raw-yuv
Fields
name |
type |
values |
converter |
description |
format |
string |
|
colorspace |
fourcc, interlaced, view-positions, chroma-site, color-matrix |