Audio lagging with ffmpeg

[Predictability]

I'm trying to record some touhou gameplay on my laptop, using (from this thread)

ffmpeg -f x11grab -framerate 60 -video_size 640x480 -i :0.0+2,23 -f pulse -i default -vcodec libx264 -preset ultrafast -qp 0 -acodec copy [VIDEO].mkv

to record and

ffmpeg -i [VIDEO].mkv -tune touhou -vcodec libx264 -preset slow -crf 24 -pix_fmt yuv420p -acodec libvorbis -aq 4 [VIDEO].mkv

to re-encode (because it's too large otherwise).

It wasn't lagging earlier today, but for some reason now the audio is about 3 seconds after the video.

Can anyone help?

Thanks in advance,
Predictability

[andrew.46]

Try using the latest git FFmpeg and if this does not solve the issue perhaps experiment with the itsoffset option:

       -itsoffset offset (input)
           Set the input time offset in seconds.  "[-]hh:mm:ss[.xxx]" syntax is also
           supported.  The offset is added to the timestamps of the input files.
           Specifying a positive offset means that the corresponding streams are delayed
           by offset seconds.

What is this btw: -tune touhou ?? I have only:

     --tune <string>         Tune the settings for a particular type of source
                              or situation
                                  Overridden by user settings.
                                  Multiple tunings are separated by commas.
                                  Only one psy tuning can be used at a time.
                                  - film (psy tuning):
                                    --deblock -1:-1 --psy-rd <unset>:0.15
                                  - animation (psy tuning):
                                    --bframes {+2} --deblock 1:1
                                    --psy-rd 0.4:<unset> --aq-strength 0.6
                                    --ref {Double if >1 else 1}
                                  - grain (psy tuning):
                                    --aq-strength 0.5 --no-dct-decimate
                                    --deadzone-inter 6 --deadzone-intra 6
                                    --deblock -2:-2 --ipratio 1.1 
                                    --pbratio 1.1 --psy-rd <unset>:0.25
                                    --qcomp 0.8
                                  - stillimage (psy tuning):
                                    --aq-strength 1.2 --deblock -3:-3
                                    --psy-rd 2.0:0.7
                                  - psnr (psy tuning):
                                    --aq-mode 0 --no-psy
                                  - ssim (psy tuning):
                                    --aq-mode 2 --no-psy
                                  - fastdecode:
                                    --no-cabac --no-deblock --no-weightb
                                    --weightp 0
                                  - zerolatency:
                                    --bframes 0 --force-cfr --no-mbtree
                                    --sync-lookahead 0 --sliced-threads
                                    --rc-lookahead 0

[Predictability]

Try using the latest git FFmpeg and if this does not solve the issue perhaps experiment with the itsoffset option:

       -itsoffset offset (input)
           Set the input time offset in seconds.  "[-]hh:mm:ss[.xxx]" syntax is also
           supported.  The offset is added to the timestamps of the input files.
           Specifying a positive offset means that the corresponding streams are delayed
           by offset seconds.

What is this btw: -tune touhou ?? I have only:

     --tune <string>         Tune the settings for a particular type of source
                              or situation
                                  Overridden by user settings.
                                  Multiple tunings are separated by commas.
                                  Only one psy tuning can be used at a time.
                                  - film (psy tuning):
                                    --deblock -1:-1 --psy-rd <unset>:0.15
                                  - animation (psy tuning):
                                    --bframes {+2} --deblock 1:1
                                    --psy-rd 0.4:<unset> --aq-strength 0.6
                                    --ref {Double if >1 else 1}
                                  - grain (psy tuning):
                                    --aq-strength 0.5 --no-dct-decimate
                                    --deadzone-inter 6 --deadzone-intra 6
                                    --deblock -2:-2 --ipratio 1.1 
                                    --pbratio 1.1 --psy-rd <unset>:0.25
                                    --qcomp 0.8
                                  - stillimage (psy tuning):
                                    --aq-strength 1.2 --deblock -3:-3
                                    --psy-rd 2.0:0.7
                                  - psnr (psy tuning):
                                    --aq-mode 0 --no-psy
                                  - ssim (psy tuning):
                                    --aq-mode 2 --no-psy
                                  - fastdecode:
                                    --no-cabac --no-deblock --no-weightb
                                    --weightp 0
                                  - zerolatency:
                                    --bframes 0 --force-cfr --no-mbtree
                                    --sync-lookahead 0 --sliced-threads
                                    --rc-lookahead 0

I seemed to have fixed it, it was an option I must have accidentally set in pavucontrol. Thanks for your help, though. I'll try using -itsoffset if it's persistent.

What is this btw: -tune touhou ??

There's hidden "tune" value in x264 video codec (free implementation of H.264) that changes codec's settings in the way that gives better quality if used for encoding replays from the Touhou Project games (or danmaku in general)

[andrew.46]

Found it in common.c:

        else if( !strncasecmp( s, "touhou", 6 ) )
        {
            if( psy_tuning_used++ ) goto psy_failure;
            param->i_frame_reference = param->i_frame_reference > 1 ? param->i_frame_reference*2 : 1;
            param->i_deblocking_filter_alphac0 = -1;
            param->i_deblocking_filter_beta = -1;
            param->analyse.f_psy_trellis = 0.2;
            param->rc.f_aq_strength = 1.3;
            if( param->analyse.inter & X264_ANALYSE_PSUB16x16 )
                param->analyse.inter |= X264_ANALYSE_PSUB8x8;
        }

Thanks for that, I have learnt something new today