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  1. Hi,

    I want to reduce the size of dynamic animations with various quality(1080p@15mbps, 1080p@10, 720p@3, examples below) to around 300-500MB per hour. From googling I have found that I should use ffmpeg+some gui with x265 codec on high crf(~30) and avcodec on quality 4. Now I have a few questions:

    1) Are my findings correct? or would you suggest a different approach?
    2) Should I resize the videos to 360p/480p/720p or leave them at source resolution?
    3) Should I include some additional settings or just let crf take care of everything?
    4) Anything else I should pay attention to?

    Thanks in advance.

    Example 1
    Code:
    General
    Format                                   : MPEG-4
    Format profile                           : Base Media / Version 2
    Codec ID                                 : mp42 (isom/iso2/avc1/mp41)
    File size                                : 8.81 GiB
    Duration                                 : 1 h 23 min
    Overall bit rate mode                    : Variable
    Overall bit rate                         : 15.0 Mb/s
    Writing application                      : HandBrake 1.0.3 2017022500
    
    Video
    ID                                       : 1
    Format                                   : AVC
    Format/Info                              : Advanced Video Codec
    Format profile                           : Main@L4
    Format settings                          : CABAC / 4 Ref Frames
    Format settings, CABAC                   : Yes
    Format settings, Reference frames        : 4 frames
    Codec ID                                 : avc1
    Codec ID/Info                            : Advanced Video Coding
    Duration                                 : 1 h 23 min
    Bit rate                                 : 14.8 Mb/s
    Width                                    : 1 920 pixels
    Height                                   : 1 080 pixels
    Display aspect ratio                     : 16:9
    Frame rate mode                          : Constant
    Frame rate                               : 60.000 FPS
    Color space                              : YUV
    Chroma subsampling                       : 4:2:0
    Bit depth                                : 8 bits
    Scan type                                : Progressive
    Bits/(Pixel*Frame)                       : 0.119
    Stream size                              : 8.71 GiB (99%)
    Writing library                          : x264 core 148 r2708 86b7198
    Encoding settings                        : cabac=1 / ref=1 / deblock=1:0:0 / analyse=0x1:0x111 / me=hex / subme=2 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=0 / me_range=16 / chroma_me=1 / trellis=0 / 8x8dct=0 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=0 / threads=6 / lookahead_threads=2 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=3 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=1 / keyint=600 / keyint_min=60 / scenecut=40 / intra_refresh=0 / rc_lookahead=10 / rc=crf / mbtree=1 / crf=16.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / vbv_maxrate=20000 / vbv_bufsize=25000 / crf_max=0.0 / nal_hrd=none / filler=0 / ip_ratio=1.40 / aq=1:1.00
    Color range                              : Limited
    Color primaries                          : BT.709
    Transfer characteristics                 : BT.709
    Matrix coefficients                      : BT.709
    Codec configuration box                  : avcC
    
    Audio
    ID                                       : 2
    Format                                   : AAC LC
    Format/Info                              : Advanced Audio Codec Low Complexity
    Codec ID                                 : mp4a-40-2
    Duration                                 : 1 h 23 min
    Bit rate mode                            : Variable
    Bit rate                                 : 158 kb/s
    Channel(s)                               : 2 channels
    Channel layout                           : L R
    Sampling rate                            : 48.0 kHz
    Frame rate                               : 46.875 FPS (1024 SPF)
    Compression mode                         : Lossy
    Stream size                              : 94.9 MiB (1%)
    Title                                    : Stereo / Stereo
    Language                                 : English
    Default                                  : Yes
    Alternate group                          : 1
    Example 2
    Code:
    General
    Format                                   : MPEG-4
    Format profile                           : Base Media / Version 2
    Codec ID                                 : mp42 (mp42/isom)
    File size                                : 1.37 GiB
    Duration                                 : 29 min 18 s
    Overall bit rate mode                    : Variable
    Overall bit rate                         : 6 669 kb/s
    
    Video
    ID                                       : 2
    Format                                   : AVC
    Format/Info                              : Advanced Video Codec
    Format profile                           : High@L4.2
    Format settings                          : CABAC / 2 Ref Frames
    Format settings, CABAC                   : Yes
    Format settings, Reference frames        : 2 frames
    Muxing mode                              : Container profile=High@4.0
    Codec ID                                 : avc1
    Codec ID/Info                            : Advanced Video Coding
    Duration                                 : 29 min 18 s
    Bit rate mode                            : Variable
    Bit rate                                 : 6 341 kb/s
    Maximum bit rate                         : 26.0 Mb/s
    Width                                    : 1 920 pixels
    Height                                   : 1 080 pixels
    Display aspect ratio                     : 16:9
    Frame rate mode                          : Constant
    Frame rate                               : 59.940 (60000/1001) FPS
    Color space                              : YUV
    Chroma subsampling                       : 4:2:0
    Bit depth                                : 8 bits
    Scan type                                : Progressive
    Bits/(Pixel*Frame)                       : 0.051
    Stream size                              : 1.30 GiB (95%)
    Language                                 : English
    Codec configuration box                  : avcC
    
    Audio
    ID                                       : 1
    Format                                   : AAC LC
    Format/Info                              : Advanced Audio Codec Low Complexity
    Codec ID                                 : mp4a-40-2
    Duration                                 : 29 min 18 s
    Bit rate mode                            : Constant
    Bit rate                                 : 320 kb/s
    Channel(s)                               : 2 channels
    Channel layout                           : L R
    Sampling rate                            : 48.0 kHz
    Frame rate                               : 46.875 FPS (1024 SPF)
    Compression mode                         : Lossy
    Stream size                              : 67.1 MiB (5%)
    Language                                 : English
    Example 3
    Code:
    General
    Format                                   : MPEG-4
    Format profile                           : Base Media / Version 2
    Codec ID                                 : mp42 (isom/iso2/mp41)
    File size                                : 1.55 GiB
    Duration                                 : 1 h 14 min
    Overall bit rate mode                    : Variable
    Overall bit rate                         : 2 977 kb/s
    Writing application                      : HandBrake 0.10.5 2016021100
    
    Video
    ID                                       : 1
    Format                                   : HEVC
    Format/Info                              : High Efficiency Video Coding
    Format profile                           : Main@L4@Main
    Codec ID                                 : hev1
    Codec ID/Info                            : High Efficiency Video Coding
    Duration                                 : 1 h 14 min
    Bit rate                                 : 2 652 kb/s
    Width                                    : 1 280 pixels
    Height                                   : 720 pixels
    Display aspect ratio                     : 16:9
    Frame rate mode                          : Variable
    Frame rate                               : 59.940 (60000/1001) FPS
    Minimum frame rate                       : 29.980 FPS
    Maximum frame rate                       : 59.960 FPS
    Color space                              : YUV
    Chroma subsampling                       : 4:2:0
    Bit depth                                : 8 bits
    Bits/(Pixel*Frame)                       : 0.048
    Stream size                              : 1.38 GiB (89%)
    Writing library                          : x265 1.9:[Windows][GCC 4.9.0][64 bit] 8bit
    Encoding settings                        : wpp / ctu=64 / min-cu-size=8 / max-tu-size=32 / tu-intra-depth=2 / tu-inter-depth=2 / me=3 / subme=3 / merange=57 / rect / amp / max-merge=3 / temporal-mvp / no-early-skip / rdpenalty=0 / no-tskip / no-tskip-fast / strong-intra-smoothing / no-lossless / no-cu-lossless / no-constrained-intra / no-fast-intra / open-gop / no-temporal-layers / interlace=0 / keyint=600 / min-keyint=60 / scenecut=40 / rc-lookahead=30 / lookahead-slices=4 / bframes=8 / bframe-bias=0 / b-adapt=2 / ref=4 / limit-refs=2 / limit-modes / weightp / weightb / aq-mode=1 / qg-size=32 / aq-strength=1.00 / cbqpoffs=0 / crqpoffs=0 / rd=6 / psy-rd=2.00 / rdoq-level=2 / psy-rdoq=1.00 / signhide / deblock / sao / no-sao-non-deblock / b-pyramid / cutree / no-intra-refresh / rc=crf / crf=18.0 / qcomp=0.60 / qpmin=0 / qpmax=51 / qpstep=4 / ipratio=1.40 / pbratio=1.30
    Color range                              : Limited
    Color primaries                          : BT.709
    Transfer characteristics                 : BT.709
    Matrix coefficients                      : BT.709
    Codec configuration box                  : hvcC
    
    Audio
    ID                                       : 2
    Format                                   : AAC LC
    Format/Info                              : Advanced Audio Codec Low Complexity
    Codec ID                                 : mp4a-40-2
    Duration                                 : 1 h 14 min
    Bit rate mode                            : Variable
    Bit rate                                 : 315 kb/s
    Channel(s)                               : 2 channels
    Channel layout                           : L R
    Sampling rate                            : 48.0 kHz
    Frame rate                               : 46.875 FPS (1024 SPF)
    Compression mode                         : Lossy
    Stream size                              : 168 MiB (11%)
    Title                                    : Stereo / Stereo
    Default                                  : Yes
    Alternate group                          : 1
    Quote Quote  
  2. When you encode short samples the way you propose, are the results acceptable to you?
    Quote Quote  
  3. Reencode video stream only, leave the audio streams as they are.
    1) 1920x1080, x264, CRF 27, frame Rate 30fps
    2) 1920x1080, x264, CRF 27, frame rate 29.97fps
    3) 1280x720, x264, CRF 24, frame rate 29.97fps
    Quote Quote  
  4. Your first clip says that it's 1hr23min 1080p60 with a file size of nearly 9GB and you want to reduce that to 300-500 mb, which works out to 18-27 times smaller. Since the file you have is 15 mb/s, that means you need to reduce the bit rate to 555kb to 833kb for 1080p60!!! I don't care what codec you use or what settings, that is going to look like crap!
    Quote Quote  
  5. I want to thank you for your time, but... Ehhh, I was counting for someone who had done similar before and is willing to share the experiences.
    Smrpix, I appreciate advice "if it's good enough, don't waste more time tweaking it and over-optimizing it", it's very good one, but it's not what I'm looking for.
    ProWo, your advice is just outright harmful. The input files which I have are from many sources and audio is unknown, it can be much crazier than what I posted. 2) and 3) have 320 kbps audio which weighs 144MB per hour. You are suggesting placebo quality audio taking 30-50% of the intended filesize. Due to your comment I included x264 in testing and now I have clear view of advantages/disadvantages of both codecs. x265 is better looking at only quality per bitrate, but results in worse playback experience. Thanks for x264 suggestion.
    sophisticles, The entire point of codecs is to reduce the filesize at the cost of playback performance. No, the result won't look like "crap' because input is high quality... Yes, result will look much worse, but that's normal and reason isn't high quality source. I accept it.

    In the end, I set up short tests with x264 and x265 to compare the quality and size between different resolutions and crf settings. You can find the script, results, settings and files below. My subjective opinion after looking at videos with desired bitrate(~550kbp, green color in pivot) in somehow random testing are that
    1) x265 has better quality than x264 at a similar bitrate and resolution
    2) higher resolution results in better details during static scenes and increase artifacts during movement
    So the "optimal" setting for me will be x265 with crf selected to acceptable level of movement artifacts and resolution reduced to obtained desired size. It will be something around 480p at crf=20 to 720p at crf=25.
    Now I have to decide how important fast seeking is and if enabling fastdecode/keyint/b-frames is worth it. Or if switching to x264 would be better. If someone knows about these or could point me in the right direction I would be grateful.

    The script can be run in powershell with argument-executionpolicy bypass. So [Win]+[R]
    Code:
    powershell -executionpolicy bypass
    enter, travel to the desired folder and run script.

    Code:
    $resolutions = "144", "360", "480", "720", "1080", "0"
    
    foreach ($resolution in $resolutions) {
        for($crf = 15; $crf -lt 51; $crf += 5){ 
            $con = '_'+$resolution+'_'+$crf+'.mp4'
            $output = ".\x265"+$con
            ffmpeg -ss 02:50 -i .\input.mp4 -map 0 -vf scale=-8:$resolution -c:v libx265 -preset fast -x265-params crf=$crf -strict -2 -movflags faststart -c:a libopus -ac 2 -b:a 128k -vbr on -compression_level 10 -codec:s copy -t 10 $output
            $output = ".\x264"+$con
            ffmpeg -ss 02:50 -i .\input.mp4 -map 0 -vf scale=-8:$resolution -c:v libx264 -preset fast -x264-params crf=$crf -strict -2 -movflags faststart -c:a libopus -ac 2 -b:a 128k -vbr on -compression_level 10 -codec:s copy -t 10 $output
        }
    }
    Image
    [Attachment 53952 - Click to enlarge]


    csv of results
    Code:
    Size,Audio Size,Video Size,Video bitrate,Resolution,CRF,Codec
    3742,300,3442,2754,1080,20,x264
    2853,300,2553,2043,1080,20,x265
    2219,300,1919,1535,1080,25,x264
    2033,300,1733,1386,720,20,x264
    1704,300,1404,1123,1080,25,x265
    1694,300,1394,1115,720,20,x265
    1422,300,1122,898,1080,30,x264
    1292,300,992,793,720,25,x264
    1248,300,948,758,480,20,x264
    1124,300,824,659,480,20,x265
    1114,300,814,651,1080,30,x265
    1104,300,804,643,720,25,x265
    1012,300,712,569,1080,35,x264
    948,300,648,518,360,20,x264
    902,300,602,482,720,30,x264
    878,300,578,462,360,20,x265
    863,300,563,450,480,25,x264
    806,300,506,405,1080,35,x265
    795,300,495,396,480,25,x265
    790,300,490,392,1080,40,x264
    786,300,486,389,720,30,x265
    692,300,392,314,720,35,x264
    692,300,392,314,360,25,x264
    656,300,356,285,360,25,x265
    649,300,349,279,480,30,x264
    646,300,346,277,1080,45,x264
    639,300,339,271,1080,40,x265
    614,300,314,251,720,35,x265
    612,300,312,250,480,30,x265
    571,300,271,217,720,40,x264
    556,300,256,205,1080,50,x264
    548,300,248,198,1080,45,x265
    546,300,246,197,360,30,x264
    531,300,231,184,480,35,x264
    530,300,230,184,360,30,x265
    513,300,213,170,1080,50,x265
    512,300,212,169,720,40,x265
    506,300,206,165,480,35,x265
    505,300,205,164,144,20,x264
    502,300,202,161,144,20,x265
    491,300,191,153,720,45,x264
    465,300,165,132,360,35,x264
    461,300,161,129,480,40,x264
    456,300,156,125,360,35,x265
    455,300,155,124,720,45,x265
    447,300,147,117,720,50,x264
    443,300,143,115,480,40,x265
    437,300,137,110,144,25,x265
    433,300,133,107,144,25,x264
    432,300,132,106,720,50,x265
    417,300,117,94,360,40,x264
    416,300,116,93,480,45,x264
    413,300,113,90,360,40,x265
    408,300,108,86,480,45,x265
    398,300,98,78,144,30,x265
    394,300,94,75,480,50,x265
    393,300,93,74,480,50,x264
    392,300,92,74,144,30,x264
    389,300,89,71,360,45,x265
    388,300,88,70,360,45,x264
    379,300,79,64,360,50,x265
    375,300,75,60,144,35,x265
    372,300,72,58,360,50,x264
    369,300,69,55,144,35,x264
    363,300,63,50,144,40,x265
    356,300,56,45,144,40,x264
    356,300,56,45,144,45,x265
    353,300,53,42,144,50,x265
    349,300,49,39,144,45,x264
    345,300,45,36,144,50,x264
    encode testing.zip
    Last edited by alfik0; 25th Jun 2020 at 11:00. Reason: acknowledge ProWo point
    Quote Quote  
  6. ProWo, your advice is just outright harmful. The input files which I have are from many sources and audio is unknown, it can be much crazier than what I posted. 2) and 3) have 320 kbps audio which weighs 144MB per hour.
    For the audio, reencode it to 192 aac. You can use for all conversions (audio and video) and remuxing my clever FFmpeg-GUI.
    Quote Quote  
  7. Originally Posted by ProWo View Post
    ProWo, your advice is just outright harmful. The input files which I have are from many sources and audio is unknown, it can be much crazier than what I posted. 2) and 3) have 320 kbps audio which weighs 144MB per hour.
    For the audio, reencode it to 192 aac. You can use for all conversions (audio and video) and remuxing my clever FFmpeg-GUI.
    192kbps still takes 28.8% if the intended filesize is 300MB. I think 128(20%) is already a bit of overkill, when in ABX testing it's difficult to notice higher bitrates completely focusing on music.

    PS: yup, I will settle at 96kbps(15%) since I value audio quality. Although something around 70 probably would be "optimal" according to this and this topic.
    PSS: reading about this, I will also probably reencode my music collection from 320 to 128...
    Last edited by alfik0; 25th Jun 2020 at 13:21. Reason: added PS and PSS
    Quote Quote  



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