Reduce File Size from 21.GB and 10 hours of video..

[mindphasar]

Hi guys,

I would like to reduce the size of this file: 10 hours for 21.8 GiB. The audio part (AAC) will be copied with ffmpeg but I have no idea what settings to use to maintain the video quality and reduce the file size I I chose the resolution 720x408 but is correct ?

Which settings should I use with x264 or x265?

Thanks


Format : MPEG-4
Format profile : Base Media
Codec ID : isom (isom/iso2/avc1/mp41)
File size : 21,8 GiB
Duration : 10 o 8 min
Overall bit rate : 5.135 kb/s
Writing application : Lavf58.33.100

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.2
Format settings : CABAC / 1 Ref Frames
Format settings, CABAC : Si
Format settings, RefFrames : 1 frame
Format settings, GOP : M=1, N=30
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 10 o 8 min
Bit rate : 5.034 kb/s
Width : 1.920 pixel
Height : 1.080 pixel
Display aspect ratio : 16:9
Frame rate mode : Variabile
Frame rate : 42,547 FPS
Minimum frame rate : 0,016 FPS
Maximum frame rate : 62,500 FPS
Original frame rate : 60,000 FPS
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bit
Scan type : Progressive
Bits/(Pixel*Frame) : 0.057
Stream size : 21,4 GiB (98%)
Codec configuration box : avcC

[Sharc]

I would like to reduce the size of this file: 10 hours for 21.8 GiB. The audio part (AAC) will be copied with ffmpeg but I have no idea what settings to use to maintain the video quality and reduce the file size I I chose the resolution 720x408 but is correct ?

Impossible. You can't reduce the video file size and keep the quality.
- Recoding the video to a smaller filesize will always reduce the quality to some extent, depending on the compression.
- Downscaling 1920x1080 to 720x408 will reduce the resolution and loose the details

[mindphasar]

Thank for you reply

[mindphasar]

I would like to reduce the size of this file: 10 hours for 21.8 GiB. The audio part (AAC) will be copied with ffmpeg but I have no idea what settings to use to maintain the video quality and reduce the file size I I chose the resolution 720x408 but is correct ?

Impossible. You can't reduce the video file size and keep the quality.
- Recoding the video to a smaller filesize will always reduce the quality to some extent, depending on the compression.
- Downscaling 1920x1080 to 720x408 will reduce the resolution and loose the details

these settings can be ok ?

-preset veryslow -profile high -level 42 -g 30 -r 30000/1001 -flags +ilme+ildct -pix_fmt yuv420p -filter_complexb scale=interl=1,fieldorder=tff,setsar=sar=40/33 -refs 8 -x264-params -crf 20 -x264opts bluray-compat=1:vbv-bufsize=30000:vbv-maxrate=40000lices=4pen-gop=1:force-cfr=1:merange=32:qcomp=0.90:colorprim=bt709:colorm atrix=bt709:transfer=bt709 -acodec copy -s 720x408

[jagabo]

Converting to HEVC with x265 will probably let you shrink it by about 30 percent (at the same frame size) without too much loss of quality. Use the slowest preset you can stand.

Using a reduced frame size is trading off resolution to get less encoding artifacts (if at the same bitrate). But reducing the frame size is in and of itself a reduction of quality. If your source isn't real sharp you can reduce the frame size without much loss of quality. So reducing the frame size to 1280x720 and encoding with x265 at 1/2 the bitrate, maybe even 1/3, probably won't hurt the video much.