VideoHelp Forum

Try DVDFab and download streaming video, copy, convert or make Blu-rays,DVDs! Download free trial !
+ Reply to Thread
Results 1 to 5 of 5
Thread
  1. 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
    Quote Quote  
  2. Originally Posted by mindphasar View Post
    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
    Quote Quote  
  3. Thank for you reply
    Last edited by mindphasar; 21st Dec 2019 at 09:29.
    Quote Quote  
  4. Originally Posted by Sharc View Post
    Originally Posted by mindphasar View Post
    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
    Quote Quote  
  5. 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.
    Quote Quote  



Similar Threads