encode with X264 @ target size

[marcorocchini]

Hi cats

from my nle I'have export my video that have duration of 1 hour and 12 minutes (video.avi)

This video.avi is uncompressed YUV 4:2:2 1920x1080 25fps interlace and is 465 GB
The audio track is separated file from the video, audio.wav is a uncompressed PCM L+R audio file of 800 MB

I would like do a transcoding into a unique .mp4 file that fit a DVD of 4,7 GB so I need to encode so that the file size does not exceed the 4,5GB (I use the dvd only to save the file, not a dvd-video)

In the meantime I need this charateristics in the target .mp4 file:

- deinterlace (possibly using the yadif) and double framerate from 25fps interlaced to 50 progressive
- reduce the colorspace from 4:2:2 to 4:2:0
- reduce audio to a .mp3 or .aac codec 48Khz and 320 Kpbs
- use ffmpeg as transcoder, and X264
- use the variable bitrate for video
- use the 2° pass encoding

Please cats, what have to be the commandline of ffmpeg that do all this? thanks

[pandy]

https://trac.ffmpeg.org/wiki/Encode/H.264#twopass


I use something like this to perform dualpass - i modify script but not tested to match your requirement with separate audio file, yadif or nnedi can be add to vproc line

@setlocal
@set gop=240
@set vbitrate=2413
@set /a vbuffsiz=%vbitrate%*1
@set /a vmaxrate=20000*1

@set slice=0
@SET x264opts1="bitrate=%vbitrate%:vbv_maxrate=%vmaxrate%:vbv_bufsize=%vbuffsiz%:level=4.0:keyint=%gop%:qpmin=4:cabac=1:threads=auto:sliced_threads=0:slices=%slice%:tff=1:interlaced=0:fake-interlaced=1:no_psnr=1:no_ssim=1:bluray_compat=1:open-gop=0:pic_struct=1:aud=1:nal_hrd=vbr:force_cfr=1:fullrange=off:overscan=show:colorprim=bt709:transfer=bt709:colormatrix=bt709:fastfirstpass=1"
@SET x264opts2="bitrate=%vbitrate%:vbv_maxrate=%vmaxrate%:vbv_bufsize=%vbuffsiz%:level=4.0:keyint=%gop%:qpmin=4:cabac=1:threads=auto:sliced_threads=0:slices=%slice%:tff=1:interlaced=0:fake-interlaced=1:no_psnr=1:no_ssim=1:bluray_compat=1:open-gop=0:pic_struct=1:aud=1:nal_hrd=vbr:force_cfr=1:fullrange=off:overscan=show:colorprim=bt709:transfer=bt709:colormatrix=bt709"


@set vproc=scale=iw:ih:sws_flags=neighbor:sws_dither=0:in_range=1:out_range=1,pp=ac/dr,format=pix_fmts=yuv420p
@set aproc=aresample=resampler=soxr:osr=48000:dither_method=0

@ffmpeg.exe -y -hide_banner -loglevel 32 -stats -avoid_negative_ts 1 -i "%1" -c:v libx264 -b:v %vbitrate%k -preset:v veryslow -tune:v film -profile:v high -level:v 4.0 -x264opts:v %x264opts1% -x264-params:v %x264opts1% -pass:v 1 -passlogfile:v log_%~n1 -color_range:v 2 -pix_fmt:v yuv420p -vf %vproc% -i "%2" -af %aproc% -c:a aac -b:a 320k -shortest -movflags faststart -y -f mp4 NUL
@ffmpeg.exe -y -hide_banner -loglevel 32 -stats -avoid_negative_ts 1 -i "%1" -c:v libx264 -b:v %vbitrate%k -preset:v veryslow -tune:v film -profile:v high -level:v 4.0 -x264opts:v %x264opts2% -x264-params:v %x264opts2% -pass:v 2 -passlogfile:v log_%~n1 -color_range:v 2 -pix_fmt:v yuv420p -vf %vproc% -i "%2" -af %aproc% -c:a aac -b:a 320k -shortest -movflags faststart -y -f mp4 %~n1_.mp4
@endlocal

[marcorocchini]

oky thanks but how can modify the commandline to fit the final size into the target of 4,5 GB?

[pandy]

oky thanks but how can modify the commandline to fit the final size into the target of 4,5 GB?

Calculate bitrate and place calculated bitrate in line @set vbitrate=2413 (1kbps=1000bits) - this is for video only so sum of audio bitrate (320kbps) and small container overhead (assume 0.5%) with video must fit in desired target size (divided by number of seconds) - i have libreoffice calc sheet to do such thing but currently have no access to my desk computer - i hope it should but too chalenging for you to calculate required bitrate (there are some online bitrate calculators AFAIR).

[jagabo]

Universal:

file size = bitrate * running time

plus a little overhead for the container. If you can't do the math use a bitrate calculator.