Convert .ts file to .mp4

For using gstreamer pipeline, please try

$ gst-launch-1.0 qtmux name=mx ! filesink location=test.mp4 filesrc location= test.ts ! tsdemux name=dmx dmx. ! queue ! h264parse ! mx. dmx. !  queue ! aacparse ! faad ! audioresample ! audioconvert ! voaacenc ! mx.

Somehow audio stream has to be decompressed and compressed again. This may take more CPU usage than ffmpeg.

For ffmpeg with hardware acceleration, please check
Jetson Nano FAQ
Q: Is hardware acceleration enabled in ffmpeg?