Difference between revisions of "Using gstreamer"
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= Tips = | = Tips = | ||
== How to get 25 FPS ? == | == How to get 25 FPS ? == | ||
| − | You won't get 25 fps if autoexposure is on and local brightness not high enough: the camera will automatically lower framerate for keeping clear picture. Either lighten up, or play with image settings (notably, gain). | + | Depends on the sensor and the exposure: |
| + | * In the sensor's datasheet find resolutions that allow the required FPS. | ||
| + | * You won't get 25 fps if autoexposure is on and local brightness not high enough: the camera will automatically lower framerate for keeping clear picture. Either lighten up, or play with image settings (notably, gain). | ||
= Commandline examples = | = Commandline examples = | ||
Revision as of 14:48, 9 June 2016
GStreamer is a modular node based player as well as encoder in a single application. It is possible to create chains of so called elements with a wide range of different plugins.
Contents
GStreamer
GStreamer is a library for constructing graphs of media-handling components. The applications it supports range from simple Ogg/Vorbis playback, audio/video streaming to complex audio (mixing) and video (non-linear editing) processing.
Applications can take advantage of advances in codec and filter technology transparently. Developers can add new codecs and filters by writing a simple plugin with a clean, generic interface.
Installing GStreamer
NicoLargo made a script to automatically install all the required packages for GStreamer on Ubuntu 10.04. Should work up to for (K)Ubuntu 16.04 as well.
Tips
How to get 25 FPS ?
Depends on the sensor and the exposure:
- In the sensor's datasheet find resolutions that allow the required FPS.
- You won't get 25 fps if autoexposure is on and local brightness not high enough: the camera will automatically lower framerate for keeping clear picture. Either lighten up, or play with image settings (notably, gain).
Commandline examples
(Note: replace width and height accordingly to your camera setup and your computer's horsepower :p).
Displaying
careful with streams at higher resolution than 1920x1088
Display the cameras live video stream at its native resolution:
gst-launch-0.10 rtspsrc location=rtsp://192.168.0.9:554 ! rtpjpegdepay ! jpegdec ! queue ! ffmpegcolorspace ! xvimagesink sync=false
Display the cameras live video stream, resize to fit window (the ! videoscale element takes care of that)
gst-launch-0.10 rtspsrc location=rtsp://192.168.0.9:554 ! rtpjpegdepay ! jpegdec ! queue ! ffmpegcolorspace ! videoscale ! xvimagesink sync=false
Dumping
mjpeg dumping
gst-launch -v rtspsrc location=rtsp://192.168.0.9:554 ! queue ! rtpjpegdepay ! videorate ! capsfilter caps = "image/jpeg, framerate=(fraction)25/1, width=1024, height=768" ! queue ! matroskamux ! filesink location=/tmp/test.mkv
YUV Dumping
gst-launch -v rtspsrc location=rtsp://192.168.0.9:554 ! queue ! rtpjpegdepay ! queue ! jpegdec ! queue ! videorate ! capsfilter caps="video/x-raw-yuv, format=(fourcc)I420, width=(int)1024, height=(int)768, framerate=(fraction)25/1" ! queue ! avimux ! filesink location=/tmp/test.avi
Dump transcoding example
gst-launch filesrc location=test.mkv ! matroskademux ! queue ! jpegdec ! queue ! theoraenc bitrate=4000 ! queue ! oggmux ! filesink location=test.ogg
Live encoding
gst-launch -v rtspsrc location=rtsp://192.168.0.9:554 ! queue ! rtpjpegdepay ! queue ! jpegdec ! queue ! videorate ! capsfilter caps="video/x-raw-yuv, format=(fourcc)I420, width=(int)1024, height=(int)768, framerate=(fraction)25/1" ! queue ! theoraenc bitrate=4000 ! queue ! oggmux ! filesink location=/tmp/test1024.ogg
I did some benchmarks; a Core 2 Quad Q6600 (2.4 Ghz) is not powerful enough for h264 encoding @fullHD resolution (using 4 treads).
