GStreamer pre-record element - Examples - PreRecord
| GStreamer pre-record element |
|---|
|
| Overview |
| User Guide |
| Getting Started |
| Examples |
| Contact Us |
PreRecord example pipelines
To test the prerecord GStreamer element is necessary to change the buffering property while the pipeline is running, thus gst-launch is not the correct application to test the element.
An easy way to evaluate the functionality of prerecord GStreamer element is using GStreamer Daemon, a GStreamer framework developed by RidgeRun that allows the user to control pipeline states and element properties.
You can install Gstd and run the following examples:
Video pre-recording example
The following script is an example where the pipeline will encode video streaming to h264 to a file and the pre-record element will be pre-recording with a buf-time of 5 seconds. After 10 seconds the video pattern will change from ball to snow and the pre-record will pass the buffer data downstream.
#!/bin/bash # Pipeline definition gstd-client pipeline_create p1 videotestsrc is-live=true name=src pattern=ball ! x264enc speed-preset=ultrafast key-int-max=30 ! prerecord buf-time=5000 buffering=true on-key-frame=true name=prerecord ! queue ! mpegtsmux name=mux ! filesink location=test_x264.ts qos=false sync=false async=false # Run pipeline gstd-client pipeline_play p1 # After 10 seconds, change video pattern sleep 10 gstd-client element_set p1 src pattern snow # Allow buffer data to pass downstream gstd-client element_set p1 prerecord buffering false # Stop the pipeline after 10 seconds sleep 10 gstd-client pipeline_stop p1 # Delete pipeline gstd-client pipeline_delete p1
To run the example, copy the script on a file (prerecord-video.sh), and follow the next steps:
sudo chmod 777 prerecord-video.sh gstd & ./prerecord-video.sh
Then you can observe the recorded video with vlc for example.
Video+Audio pre-recording example
The following script is an example where the pipeline will encode video streaming to h264 and audio streaming to AAC and the pre-record element will be pre-recording with a buf-time of 5 seconds. After 10 seconds the video pattern will change from ball to snow and the pre-record will pass the buffer data downstream.
#!/bin/bash # Pipeline definition gstd-client pipeline_create p1 videotestsrc is-live=true name=src pattern=ball ! x264enc speed-preset=ultrafast key-int-max=30 ! prerecord buf-time=5000 buffering=true on-key-frame=true name=prerecord ! queue ! mpegtsmux name=mux ! filesink location=test_x264.ts qos=false sync=false async=false audiotestsrc is-live=true name=au ! opusenc ! prerecord. prerecord. ! queue ! mux. # Run pipeline gstd-client pipeline_play p1 # After 10 seconds, change video pattern and audio wave sleep 10 gstd-client element_set p1 src pattern snow gstd-client element_set p1 au wave 5 # Allow buffer data to pass downstream gstd-client element_set p1 prerecord buffering false # Stop the pipeline after 10 seconds sleep 10 gstd-client event_eos p1 gstd-client pipeline_stop p1 # Delete pipeline gstd-client pipeline_delete p1
Run the example in the same way as the first one and observe the result.
Example pipeline using filesrc
This is another example that you can use as a reference to create your own.
filesrc location=$FILE ! qtdemux name=demux ! queue ! ffdec_h264 ! x264enc speed-preset=ultrafast ! prerecord \ buf-time=5000 buffering=true on-key-frame=false name=prerecord ! qtmux name=mux ! filesink location=test1.mp4 \ async=false demux. ! ffdec_aac ! prerecord. prerecord. ! queue ! opusenc ! mux. fakesink async=false