mp4mux faststart bufsize too low
gst_qt_mux_send_buffered_data is too slow. I would love to use the "faststart" feature but this makes it impossible. I think the reason is simply the bufsize. Some of my numbers: ~1min recording (32 MB) is finalized during ~40sec, which makes the processing rate ~5ms per buffer (which is 4kB). I don't think there is much room for optimization of processing of each buffer. I've already tried buffering downstream, that doesn't help much. But using larger buffer would help, for sure. Normally I work with 1MB buffers while file copying and I am quite happy with that. I can understand why 4096 has been chosen but overhead is just too high.
Also, having the buffer 1MB is not for everyone as well, so I think it's worth having the bufsize configurable. Thanks for considering.