User:Trickygnome/Video recording

FFmpeg orders of parameters

ffmpeg [global_options] [input_options1] -i input1 [input_options2] -i input2 ... [output_options] output

check input

check and tune microphone

 arecord -D mic -f cd -d 10 test.wav && mpv test.wav

 ffmpeg -f alsa -i mic -t 10 -ac 2 -ar 44100 test.mp4 && mpv test.mp4

 ffmpeg -fflags +genpts  -f alsa -ac 2 -ar 44100 -thread_queue_size 1024 -i mic   -c:a aac -af "volume=20,anlmdn,highpass=f=1200,lowpass=f=2600,aresample=async=1"  output.mp4 ; mpv output.mp4

 ffmpeg -fflags +genpts  -use_wallclock_as_timestamps 1 \
-f alsa -ac 2 -ar 44100 -thread_queue_size 2048 -i mic  \
-c:a aac -b:a 192k -af "volume=5,anlmdn,highpass=f=1000,lowpass=f=3000,aresample=async=1000" -movflags +faststart output.mp4 ; mpv output.mp4

check camera

root #USE=sdl emerge --ask ffmpeg

sdl flag required for ffplay command

 ffplay -report -f v4l2 -video_size 1280x720 -framerate 15 -i /dev/video0

 ffmpeg -f v4l2 -video_size 1280x720 -framerate 15 -i /dev/video0 -c:v libx264 -preset ultrafast -y output.mp4

check screen recorder

Here for Wayland wlroots we use wf-recorder tool to record screen.

 wf-recorder -D -b0 -B0 -m rawvideo --pixel-format yuv420p -r 15 --geometry 1920x1080 -f aa.mp4

 ffplay -f rawvideo -pixel_format yuvj420p -video_size 1920x1080 -framerate 30 test.yuv

Recording of mixes

1) Record only microphone and camera with ffmpeg.

This gives us acceleration capabilities available:

user $ffmpeg -hwaccels

 ffmpeg -f v4l2 -thread_queue_size 30 -i /dev/video0 -f alsa -thread_queue_size 30 -i mic -c:v h264_nvenc -preset p4 -rc vbr_hq -qmin 19 -qmax 21 -b:v 5M -maxrate 8M -c:a aac -ar 16000 -b:a 192k -async 1 -af "volume=20,anlmdn,highpass=f=1000,lowpass=f=3000,aresample=async=10" output.mp4

2) Record only screen video to file. Read file in mixer and save to other file. Play result file. Use ffmpeg debugging -loglevel debug

user $ wf-recorder -D -b0 -B0 -m rawvideo --pixel-format yuv420p -r 15 --geometry 1920x1080 -f out.yuv

user $ffmpeg -i out.yuv -c:v libx264 -preset ultrafast -y output.mp4 -loglevel debug

user $mpv output.mp4

3) Pipe screen recorder to mixer

 wf-recorder -D -b0 -B0 -m rawvideo --pixel-format yuvj422p -r 15 --geometry 1920x1080 -f /dev/stdout | ffmpeg -i - -vf "format=yuvj422p" -c:v libopenh264 -y output.mp4

user $mpv output.mp4

4) Add microphone recording to screen recording with mixer

  wf-recorder -D -b0 -B0 -m rawvideo --pixel-format yuv420p -r 15 --geometry 1920x1080 -f /dev/stdout | ffmpeg -f alsa -i mic -i - -map 1:v -map 0:a -c:v libx264 -b:v 5000k -preset fast -c:a aac -b:a 128k -ar 44100 -ac 2 -shortest -y output.mp4

Finally

all at once

Almost, but NOT WORKING, FAIL.

wf-recorder -D -b0 -B0 -m rawvideo --pixel-format yuvj420p -r 15 -f /dev/stdout | ffmpeg -hwaccel cuda -fflags +genpts -use_wallclock_as_timestamps 1 -i - -f v4l2 -video_size 420x240 -framerate 15 -i /dev/video0 -f alsa -ac 2 -ar 11025 -thread_queue_size 48 -i mic -filter_complex "[0:v][1:v] overlay=W-w:H-h:format=yuv420" -map 2:a -c:v libx264 -preset fast -c:a aac -b:a 192k -af "volume=20,anlmdn,highpass=f=1000,lowpass=f=3000,aresample=async=10" -avoid_negative_ts make_zero -movflags +faststart -y output.mkv

record in parallel and then combine

FILE myrec.shFor Firefox

#!/bin/bash
trap "kill 0" SIGINT

rm -f screen.mp4
rm -f camera+mic.mp4
setsid ffmpeg -f v4l2 -thread_queue_size 30 -i /dev/video0 -f alsa -thread_queue_size 30 -i mic -c:v h264_nvenc -preset p4 -rc vbr_hq -qmin 19 -qmax 21 -b:v 5M -maxrate 8M -c:a aac -ar 16000 -b:a 192k -async 1 -af "volume=20,anlmdn,highpass=f=1000,lowpass=f=3000,aresample=async=10" -y camera+mic.mp4 &
wf-recorder -D -b0 -B0 -m rawvideo --pixel-format yuv420p -r 15 --geometry 1920x1080 -f screen.mp4 &

wait
killall ffmpeg

Combine to "screen.mp4" + "camera+mic.mp4" = output.mp4:

ffmpeg -i screen.mp4 -i camera+mic.mp4 \ -filter_complex "[0:v]setpts=PTS-STARTPTS[bg]; \ [1:v]setpts=PTS-STARTPTS,scale=320:-1[cam]; \ [bg][cam]overlay=main_w-overlay_w:main_h-overlay_h:shortest=1,format=yuv420p[outv]" \ -map "[outv]" -map 1:a -c:v libx264 -preset fast -crf 23 -c:a aac output.mp4