# Audio-video use cases The audio-video (AV) use cases show AV capture and AV playback. Before you run the use cases, ensure that you complete the preconditions mentioned in [GStreamer command-line use cases](https://docs.qualcomm.com/doc/80-80021-50/topic/gstreamer-application-use-cases.html). ## Audio-video capture (H.264 video codec and MP3 audio codec) The use cases show the AV capture where a 1080p stream from a camera is encoded as an H.264 stream, and sent to a multiplexer. The PCM `opt` is from an audio source is encoded as MP3, and sent to the multiplexer. The multiplexed files are then saved as an MP4 file. 1. In the terminal of the target device, run the use case in the SSH shell: gst-launch-1.0 -e qtiqmmfsrc ! video/x-raw,format=NV12,width=1920,height=1080,framerate=30/1,interlace-mode=progressive,colorimetry=bt601 ! queue ! v4l2h264enc capture-io-mode=4 output-io-mode=5 extra-controls="controls,video_bitrate=1000000,video_gop_size=29;" ! queue ! h264parse ! muxer. pulsesrc do-timestamp=true provide-clock=false volume=10 ! audio/x-raw,format=S16LE,channels=1,rate=48000 ! audioconvert ! queue ! lamemp3enc ! mp4mux name=muxer ! queue ! filesink location=/opt/1080p_AVC_MP3.mp4 Copy to clipboard 2. In the terminal of the Linux host computer, run the following command to pull and play the recorded content: scp -r root@[DEVICE IP-ADDR]:/opt/1080p_AVC_MP3.mp4 user1@[HOST IP-ADDR]:/workspace Copy to clipboard You can play the camera stream from the MP4 file on a media player and the audio over the speakers. To stop the use case, use **CTRL + C**. The following figure shows the flow of the pipeline execution: Qualcomm Open source v4l2h264enc h264parse qtiqmmfsrc pulsesrc audioconvert lamemp3enc aacparse mp4mux filesink GST BIN **Figure : Pipeline for AV capture–camera source and audio source** ## Audio-video playback The use case shows AV playback where the MP4 file is demultiplexed. The video stream is decoded and displayed. The audio stream is decoded and played over the speaker. The following use cases describe a single AV playback with MP3 and FLAC formats. - Run all the use cases in the SSH shell of the target device. - To stop the use cases, use **CTRL + C**. ## Single AV playback (AVC video + MP3 audio) gst-launch-1.0 -e filesrc location=/opt/.mp4 ! qtdemux name=demux demux. ! queue ! h264parse ! v4l2h264dec capture-io-mode=4 output-io-mode=4 ! waylandsink fullscreen=true demux. ! queue ! mpegaudioparse ! mpg123audiodec ! pulsesink volume=10 Copy to clipboard h264parse v4l2h264dec waylandsink queue queue mpegaudioparse mpg123audiodec pulsesink filesrc qtdemux GST BIN Qualcomm Open source **Figure : Pipeline for AV playback–AVC video + MP3 audio** ## Single AV playback (AVC video + FLAC audio) gst-launch-1.0 -e filesrc location=/opt/.mp4 ! qtdemux name=demux demux. ! queue ! h264parse ! v4l2h264dec capture-io-mode=4 output-io-mode=4 ! waylandsink fullscreen=true demux. ! queue ! flacparse ! flacdec ! pulsesink volume=10 Copy to clipboard Qualcomm Open source h264parse v4l2h264dec waylandsink queue queue flacparse flacdec pulsesink filesrc qtdemux GST BIN **Figure : Pipeline for AV playback–AVC video + FLAC audio** ## Related information [Audio-video playback](https://docs.qualcomm.com/doc/80-80021-50/topic/gst-audio-video-playback.html) Last Published: Mar 26, 2026 [Previous Topic Audio use cases](https://docs.qualcomm.com/bundle/publicresource/80-80021-50/topics/audio-use-cases.md) [Next Topic Video composition use cases](https://docs.qualcomm.com/bundle/publicresource/80-80021-50/topics/video-composition.md)