[FFmpeg-user] Decode FFV1 AVI back to DPX

Abhi Akkeneni abhi.ak145 at gmail.com
Mon Dec 7 11:04:53 CET 2015


Hello Christoph and Peter,

Thank you both for your quick responses. Apologies for replying so late,
did not have internet access till today.

So what I have done so far is encode the DPX files using FFV1 wrapped with
avi using the following cmd:

*ffmpeg -i C:\Users\Abhi\Desktop\DPX\%%01d.dpx -vcodec ffv1 -level 3 -coder
1 -pix_fmt gbrp10le -an C:\Users\Abhi\Desktop\FFv1_avi\RGBTest_AVI.avi*

I then decode the .avi back to DPX using:

*ffmpeg -i C:\Users\Abhi\Desktop\FFv1_avi\RGBTest_AVI.avi -pix_fmt gbrp10le
-vcodec dpx C:\Users\Abhi\Desktop\ffv1_restored_DPX\%%01d_AVI_restored.dpx*

*The original DPX details(Using GraphicsMagick Identify command):*

C:\Program Files (x86)\GraphicsMagick-1.3.23-Q16>gm identify -verbose
C:\Users\A
bhi\Desktop\DPX\1.dpx
Image: C:\Users\Abhi\Desktop\DPX\1.dpx
  Format: DPX (SMPTE 268M-2003 (DPX 2.0))
  Geometry: 2048x1556
  Class: DirectClass
  Type: true color
  Depth: 16 bits-per-pixel component
  Channel Depths:
    Red:      16 bits
    Green:    16 bits
    Blue:     16 bits
  Channel Statistics:
    Red:
      Minimum:                  1281.00 (0.0195)
      Maximum:                 40423.00 (0.6168)
      Mean:                     6219.86 (0.0949)
      Standard Deviation:       9262.09 (0.1413)
    Green:
      Minimum:                   320.00 (0.0049)
      Maximum:                 39910.00 (0.6090)
      Mean:                     5420.29 (0.0827)
      Standard Deviation:       9250.51 (0.1412)
    Blue:
      Minimum:                     0.00 (0.0000)
      Maximum:                 39398.00 (0.6012)
      Mean:                     5038.24 (0.0769)
      Standard Deviation:       9230.74 (0.1409)
  Filesize: 12.2Mi
  Interlace: No
  Orientation: TopLeft
  Background Color: white
  Border Color: #DFDFDFDFDFDF
  Matte Color: #BDBDBDBDBDBD
  Page geometry: 2048x1556+0+0
  Compose: Over
  Dispose: Undefined
  Iterations: 0
  Compression: Undefined
  Document: RL01_0000001.dpx
  DPX:file.version: V2.0
  DPX:file.filename: RL01_0000001.dpx
  DPX:file.creation.datetime: 2015:09:25:14:01:13:IST
  DPX:image.orientation: 0
  DPX:source.filename: /mnt/dothill_01/YEAR_2015/FOR_GRADE/09_SEP/**
2K_24FPS/250915/S1/REEL01/RL01_0000001.dpx
  DPX:source.creation.datetime: 2015:09:25:14:01:13:IST
  DPX:source.device.name: Scanity V2.7.1
  DPX:source.device.serialnumber: 133

  DPX:source.aspect.ratio.horizontal: 2048
  DPX:source.aspect.ratio.vertical: 2048
  DPX:mp.frame.position: 1
  DPX:mp.frame.rate: 24
  DPX:tv.time.code: 00:00:00:01
  DPX:tv.video.signal: 0
  DPX:user.data.id: Digital Film Technology
  Signature:
09342f3c2835c1f23379d150dd61b8e8214743ff41d4c256b0d42f9412de8276
  Profile-DPXUSERDATA: 512 bytes
  Tainted: False
  User Time: 0.031u
  Elapsed Time: 0:01
  Pixels Per Second: 98.0Mi

*Restored DPX File Detials:*

C:\Program Files (x86)\GraphicsMagick-1.3.23-Q16>gm identify -verbose
C:\Users\A
bhi\Desktop\ffv1_restored_DPX\1_AVI_restored.dpx
Image: C:\Users\Abhi\Desktop\ffv1_restored_DPX\1_AVI_restored.dpx
  Format: DPX (SMPTE 268M-2003 (DPX 2.0))
  Geometry: 2048x1556
  Class: DirectClass
  Type: true color
  Depth: 16 bits-per-pixel component
  Channel Depths:
    Red:      16 bits
    Green:    16 bits
    Blue:     16 bits
  Channel Statistics:
    Red:
      Minimum:                  1281.00 (0.0195)
      Maximum:                 40423.00 (0.6168)
      Mean:                     6219.86 (0.0949)
      Standard Deviation:       9262.09 (0.1413)
    Green:
      Minimum:                   320.00 (0.0049)
      Maximum:                 39910.00 (0.6090)
      Mean:                     5420.29 (0.0827)
      Standard Deviation:       9250.51 (0.1412)
    Blue:
      Minimum:                     0.00 (0.0000)
      Maximum:                 39398.00 (0.6012)
      Mean:                     5038.24 (0.0769)
      Standard Deviation:       9230.74 (0.1409)
  Filesize: 12.2Mi
  Interlace: No
  Orientation: TopLeft
  Background Color: white
  Border Color: #DFDFDFDFDFDF
  Matte Color: #BDBDBDBDBDBD
  Page geometry: 2048x1556+0+0
  Compose: Over
  Dispose: Undefined
  Iterations: 0
  Compression: Undefined
  Software: Lavc57.16.100
  DPX:file.version: V1.0
  DPX:file.creator: Lavc57.16.100
  DPX:image.orientation: 0
  DPX:source.x-offset: 0
  DPX:source.y-offset: 0
  DPX:source.x-center: 0
  DPX:source.y-center: 0
  DPX:source.x-original-size: 0
  DPX:source.y-original-size: 0
  DPX:source.border.validity.left: 0
  DPX:source.border.validity.right: 0
  DPX:source.border.validity.top: 0
  DPX:source.border.validity.bottom: 0
  DPX:source.aspect.ratio.horizontal: 1
  DPX:source.aspect.ratio.vertical: 1
  DPX:source.scanned.size.x: 0
  DPX:source.scanned.size.y: 0
  Signature:
09342f3c2835c1f23379d150dd61b8e8214743ff41d4c256b0d42f9412de8276
  Tainted: False

As far as color space goes, the original DPX is supposed to be a 10 bit RGB
but it shows above as 16 bits. If I open the file using Xnview it shows as
10 bit RGB but from the above it shows 16 bit. Any idea why would this be
the case?.

Is this the correct way of compressing DPX files and restoring it?. I did a
PSNR test on the original and restored file and it shows no error. Is this
alone enough to prove that it is indeed a mathematically lossless
compression?.

I hope this gives you enough information to be able to understand what I am
trying to do.

Thanks again for your help guys and I look forward to hearing what you have
to say.

Best regards,

Abhi



On Fri, Nov 27, 2015 at 1:02 AM, Peter B. <pb at das-werkstatt.com> wrote:

> On 11/26/2015 04:36 PM, Christoph Gerstbauer wrote:
> > color format has your DPX original source?
> > RGB 10bit? Linear or logarithmic?
> >
> > And which color format has the FFv1?
>
> Christoph Gerstbauer's questions are good.
> As far as I know, you might need to provide additional details when
> transcoding back from FFV1 to DPX at the moment, in order for the
> colorsspace and linear/logarithmic to be displayed correctly.
>
> Kind regards,
> Pb
> _______________________________________________
> ffmpeg-user mailing list
> ffmpeg-user at ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-user
>



-- 
Abhi P Akkeneni
Georgia Institute of Technology
BS. Electrical Engineering, Honors, May 2013


More information about the ffmpeg-user mailing list