Body: <p>Forgive me for I'm new to here, but I've been searching for solutions all the day,  yet still puzzled by this problem. I try to downscale a 3840*2160 video to 1080p, and here's what I first did: </p>
  
  <p><code>ffmpeg -i original.mkv -vf scale=1920:-1 downscaled.mkv</code></p>
  
  <p>And here are the results:</p>
  
  <p>Original:
  <a href="https://i.sstatic.net/OFm9I.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/OFm9I.jpg" alt="Original video screenshot"></a></p>
  
  <p>Downscaled:
  <a href="https://i.sstatic.net/X3wfR.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/X3wfR.jpg" alt="Downscaled video screenshot"></a></p>
  
  <p>At first, I thought it's because I didn't apply the correct settings to my video player (potplayer), but even I set exactly the same splitter/decoder/renderer/..., it still didn't work.</p>
  
  <p>Then I searched and tried different ways like  <code>pix_fmt yuv444p10le</code> which is from a <a href="https://video.stackexchange.com/questions/28889/ffmpeg-does-not-preserve-colors-after-resizing">post here</a>, and later defined encoders, crf...... but all didn't work.</p>
  
  <p><strong>Could anyone please help me, many thanks!</strong>
  <hr>
  Add: I then used HandBrake, a GUI video transcoder, to downscale the original video, it worked well, at least, looks a lot better.
  <a href="https://i.sstatic.net/YSwkI.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/YSwkI.jpg" alt="Downscaled video using HandBrake screenshot"></a></p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-02-21T11:28:02.257Z
Comments.Text: Interesting. I suspect it has something to do with the color-space you're in. The original footage might have been in srgb but then got converted into an ACES colorspace (for example), and thus the values for each color shifted a bit. You might want to try to find out the color-space of your original footage and then setting it during the downscaling with ffmpeg.
Comments.UserDisplayName: Florian Claaßen
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-02-21T14:07:12.600Z
Comments.Text: Share the readout of `ffmpeg -i original.mkv `
Comments.UserDisplayName: Gyan
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-02-22T02:41:39.740Z
Comments.Text: @Gyan too long to comment, so I'll separately comment.
Comments.UserDisplayName: Xiaobao
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-02-22T02:43:34.163Z
Comments.Text: `Metadata:
      title           : Frozen.II.2019.2160p.BluRay.REMUX.HEVC.DTS-HD.MA.TrueHD.7.1.Atmos-FGT
      ENCODER         : Lavf58.35.101
    Duration: 00:01:40.64, start: 0.000000, bitrate: 68129 kb/s
      Chapter #0:0: start 0.000000, end 100.000000
      Metadata:
        title           : Chapter 15
      Stream #0:0(eng): Video: hevc (Main 10), yuv420p10le(tv, bt2020nc/bt2020/smpte2084), 3840x2160 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 1k tbn, 23.98 tbc`
Comments.UserDisplayName: Xiaobao
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-02-22T02:44:54.693Z
Comments.Text: `Metadata:
        title           : Frozen.II.2019.2160p.BluRay.REMUX.HEVC.DTS-HD.MA.TrueHD.7.1.Atmos-FGT
        BPS-eng         : 60669047
        DURATION-eng    : 01:43:13.646000000
        NUMBER_OF_FRAMES-eng: 148499
        NUMBER_OF_BYTES-eng: 46970325317
        _STATISTICS_WRITING_APP-eng: mkvmerge v43.0.0 ('The Quartermaster') 64-bit
        _STATISTICS_WRITING_DATE_UTC-eng: 2020-02-15 09:08:44
        _STATISTICS_TAGS-eng: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES
        DURATION   : 00:01:40.642000000
      Stream #0:1(eng): Audio: truehd, 48000 Hz, 7.1, s32 (24 bit) (default)`
Comments.UserDisplayName: Xiaobao
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-02-22T02:45:31.690Z
Comments.Text: `Metadata:
        title           : Frozen.II.2019.2160p.BluRay.REMUX.HEVC.DTS-HD.MA.TrueHD.7.1.Atmos-FGT
        BPS-eng         : 8448778
        DURATION-eng    : 01:43:13.646000000
        NUMBER_OF_FRAMES-eng: 7432376
        NUMBER_OF_BYTES-eng: 6541093050
        _STATISTICS_WRITING_APP-eng: mkvmerge v43.0.0 ('The Quartermaster') 64-bit
        _STATISTICS_WRITING_DATE_UTC-eng: 2020-02-15 09:08:44
        _STATISTICS_TAGS-eng: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES
        DURATION        : 00:01:40.336000000
      Stream #0:2(eng): Subtitle: subrip (default)`
Comments.UserDisplayName: Xiaobao
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-02-22T02:45:52.263Z
Comments.Text: `Metadata:
        title           : English-SRT
        BPS-eng         : 53
        DURATION-eng    : 01:41:34.123000000
        NUMBER_OF_FRAMES-eng: 1562
        NUMBER_OF_BYTES-eng: 40405
        _STATISTICS_WRITING_APP-eng: mkvmerge v43.0.0 ('The Quartermaster') 64-bit
        _STATISTICS_WRITING_DATE_UTC-eng: 2020-02-15 09:08:44
        _STATISTICS_TAGS-eng: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES
        DURATION        : 00:01:39.221000000`
Comments.UserDisplayName: Xiaobao
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-02-24T21:30:39.210Z
Comments.Text: You should [edit] your question to add this info instead of trying to cram it in multiple comments.
Comments.UserDisplayName: llogan
Tags: <ffmpeg><video-quality><color-correction><handbrake>
Title: Color loss and grayish after downscaling using ffmpeg
UserDisplayName: Xiaobao
ThreadText: # Color loss and grayish after downscaling using ffmpeg
  
  (Asked by: username_0 on 2020-02-21)
  
  Forgive me for I'm new to here, but I've been searching for solutions all the day, yet still puzzled by this problem. I try to downscale a 3840\*2160 video to 1080p, and here's what I first did:
  
  `ffmpeg -i original.mkv -vf scale=1920:-1 downscaled.mkv`
  
  And here are the results:
  
  Original:
  [![Original video screenshot](https://i.sstatic.net/OFm9I.jpg)](https://i.sstatic.net/OFm9I.jpg)
  
  Downscaled:
  [![Downscaled video screenshot](https://i.sstatic.net/X3wfR.jpg)](https://i.sstatic.net/X3wfR.jpg)
  
  At first, I thought it's because I didn't apply the correct settings to my video player (potplayer), but even I set exactly the same splitter/decoder/renderer/..., it still didn't work.
  
  Then I searched and tried different ways like `pix_fmt yuv444p10le` which is from a [post here](https://video.stackexchange.com/questions/28889/ffmpeg-does-not-preserve-colors-after-resizing), and later defined encoders, crf...... but all didn't work.
  
  **Could anyone please help me, many thanks!**
  
  ---
  
  Add: I then used HandBrake, a GUI video transcoder, to downscale the original video, it worked well, at least, looks a lot better.
  [![Downscaled video using HandBrake screenshot](https://i.sstatic.net/YSwkI.jpg)](https://i.sstatic.net/YSwkI.jpg)
  
  **Tags:** ffmpeg, video-quality, color-correction, handbrake
  
  > **Comments:**
  > **username_1**: Interesting. I suspect it has something to do with the color-space you're in. The original footage might have been in srgb but then got converted into an ACES colorspace (for example), and thus the values for each color shifted a bit. You might want to try to find out the color-space of your original footage and then setting it during the downscaling with ffmpeg.  
  > **username_2**: Share the readout of `ffmpeg -i original.mkv `  
  > **username_0**: @username_2 too long to comment, so I'll separately comment.  
  > **username_0**: `Metadata:     title           : Frozen.II.2019.2160p.BluRay.REMUX.HEVC.DTS-HD.MA.TrueHD.7.1.Atmos-FGT     ENCODER         : Lavf58.35.101   Duration: 00:01:40.64, start: 0.000000, bitrate: 68129 kb/s     Chapter #0:0: start 0.000000, end 100.000000     Metadata:       title           : Chapter 15     Stream #0:0(eng): Video: hevc (Main 10), yuv420p10le(tv, bt2020nc/bt2020/smpte2084), 3840x2160 [SAR 1:1 DAR 16:9], 23.98 fps, 23.98 tbr, 1k tbn, 23.98 tbc`  
  > **username_0**: `Metadata:       title           : Frozen.II.2019.2160p.BluRay.REMUX.HEVC.DTS-HD.MA.TrueHD.7.1.Atmos-FGT       BPS-eng         : 60669047       DURATION-eng    : 01:43:13.646000000       NUMBER_OF_FRAMES-eng: 148499       NUMBER_OF_BYTES-eng: 46970325317       _STATISTICS_WRITING_APP-eng: mkvmerge v43.0.0 ('The Quartermaster') 64-bit       _STATISTICS_WRITING_DATE_UTC-eng: 2020-02-15 09:08:44       _STATISTICS_TAGS-eng: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES       DURATION   : 00:01:40.642000000     Stream #0:1(eng): Audio: truehd, 48000 Hz, 7.1, s32 (24 bit) (default)`  
  > **username_0**: `Metadata:       title           : Frozen.II.2019.2160p.BluRay.REMUX.HEVC.DTS-HD.MA.TrueHD.7.1.Atmos-FGT       BPS-eng         : 8448778       DURATION-eng    : 01:43:13.646000000       NUMBER_OF_FRAMES-eng: 7432376       NUMBER_OF_BYTES-eng: 6541093050       _STATISTICS_WRITING_APP-eng: mkvmerge v43.0.0 ('The Quartermaster') 64-bit       _STATISTICS_WRITING_DATE_UTC-eng: 2020-02-15 09:08:44       _STATISTICS_TAGS-eng: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES       DURATION        : 00:01:40.336000000     Stream #0:2(eng): Subtitle: subrip (default)`  
  > **username_0**: `Metadata:       title           : English-SRT       BPS-eng         : 53       DURATION-eng    : 01:41:34.123000000       NUMBER_OF_FRAMES-eng: 1562       NUMBER_OF_BYTES-eng: 40405       _STATISTICS_WRITING_APP-eng: mkvmerge v43.0.0 ('The Quartermaster') 64-bit       _STATISTICS_WRITING_DATE_UTC-eng: 2020-02-15 09:08:44       _STATISTICS_TAGS-eng: BPS DURATION NUMBER_OF_FRAMES NUMBER_OF_BYTES       DURATION        : 00:01:39.221000000`  
  > **username_3**: You should [edit] your question to add this info instead of trying to cram it in multiple comments.  
  
  ---
  
  ## 0 answers
  
  