Low FPS output using ffmpeg and a raspi camera - ffmpeg

Question

I am building a surveillance camera for a school project, which is based on a raspberry pi and a infrared raspberry Pi camera.
I am capturing the camera's video stream and outputting it as an HLS stream directly from ffmpeg. However, the resulting video is really low fps (~5 at max)
Strangely, raspivid manages to ouput a 60fps 720p stream without any problem, but when put through ffmpeg for streaming, the video is cropped in half and i cannot get it to show up entirely.
Here is the ffmpeg command i use:
#!/bin/bash
ffmpeg -v verbose \
-re \
-i /dev/video0 \
-c:v libx264 \
-an \
-f hls \
-g 10 \
-sc_threshold 0 \
-hls_time 1 \
-hls_list_size 4 \
-hls_delete_threshold 1 \
-hls_flags delete_segments \
-hls_start_number_source datetime \
-hls_wrap 15 \
-preset superfast \
-start_number 1 \
/home/pi/serv/assets/stream.m3u8
And the resulting log output (notice the fps)
Here is the command using raspivid that i tested, based on a blog post i read:
raspivid -n \
-t 0 \
-w 960 \
-h 540 \
-fps 25 \
-o - | ffmpeg \
-v verbose \
-i - \
-vcodec copy \
-an \
-f hls \
-g 10 \
-sc_threshold 0 \
-hls_time 1 \
-hls_list_size 4 \
-hls_delete_threshold 1 \
-hls_flags delete_segments \
-hls_start_number_source datetime \
-hls_wrap 15 \
-preset superfast \
-start_number 1 \
/home/pi/serv/assets/stream.m3u8
I am not a ffmpeg expert and am open to any suggestions that would help improve the stream's quality and stability :)