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. <p...@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
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