[FFmpeg-user] Decode FFV1 AVI back to DPX

Christoph Gerstbauer christophgerstbauer at gmail.com
Mon Dec 7 13:36:11 CET 2015


Hello Abhi,

can you give me/us an DPX sample (one singular DPX file which 
respresents the source), just to check if it is 16 or 10bit.

You can test if you get the orginal dpx files back via the framemd5 
option in ffmpeg.
You make for every frame an md5 checksum via:
ffmpeg -i inputfile -an -f framemd5 outputtextfile.txt

Do this for the inputs DPX sequence and for the output dpx sequence.
Then compare both files -> If the txt files are equal, then it was lossless.

Comparing can be done for example with notepad++ inlcuding the COMPARE 
plugin (both open source).

But: Do your DPX file have linear or logarithmic values?
You may check this with MEDIAINFO. (also open source)
If the values are/were logarithmic -> then the backtranscodng to DPX 
will not be lossless.

Best Regards
Christoph Gerstbauer



Am 07.12.2015 um 11:04 schrieb Abhi Akkeneni:
> 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
>>
>
>



More information about the ffmpeg-user mailing list