Does ImageMagick support this specific DPX format?
Posted: 2011-08-16T16:19:35-07:00
Hello,
I retrieved raw video buffer data from a video capture card. According to it, it is 12 bit DPX big endian format.
To be able to confirm that, I appended a DPX header from other file and modified header information accordingly.
The bit stream doesn't look Method A where 4 bits of 0s were padded at the LSB side. ( because there is no pattern in 2 byte boundary that the low 4 bits, nibble, are 0 always. )
It can't be Method B, either.
So, I think it is 32 bit packed format. which is set as "0" (field 21.10, offset 804, 2 bytes ).
When I visually checked it with ImageMagick, ( it converts the DPX file to 8 bit format first, of course ), it showed the visual content, but lost most of colors ( it should be black background mostly, while the portion of painted white wall on its right side was lighted in red color. ) and it looked like interlaced horizontally, i.e. shows vertical lines.
If it is not 32 bit packed format, it should be displayed with totally wrongly, but shape-wise it is correct.
So, actually what I wanted to ask is if anybody tell me what could be the cause or if 12 bit DPX in 32bit packed format is supported properly.
Thank you.
https://docs.google.com/leaf?id=0B9gIhE ... ist&num=50
<Fig. 1> Correct Image
https://docs.google.com/leaf?id=0B9gIhE ... z&hl=en_US
<Fig.2> What is actually displayed
https://docs.google.com/leaf?id=0B9gIhE ... w&hl=en_US
<Fig.3> The dpx file
I retrieved raw video buffer data from a video capture card. According to it, it is 12 bit DPX big endian format.
To be able to confirm that, I appended a DPX header from other file and modified header information accordingly.
The bit stream doesn't look Method A where 4 bits of 0s were padded at the LSB side. ( because there is no pattern in 2 byte boundary that the low 4 bits, nibble, are 0 always. )
It can't be Method B, either.
So, I think it is 32 bit packed format. which is set as "0" (field 21.10, offset 804, 2 bytes ).
When I visually checked it with ImageMagick, ( it converts the DPX file to 8 bit format first, of course ), it showed the visual content, but lost most of colors ( it should be black background mostly, while the portion of painted white wall on its right side was lighted in red color. ) and it looked like interlaced horizontally, i.e. shows vertical lines.
If it is not 32 bit packed format, it should be displayed with totally wrongly, but shape-wise it is correct.
So, actually what I wanted to ask is if anybody tell me what could be the cause or if 12 bit DPX in 32bit packed format is supported properly.
Thank you.
https://docs.google.com/leaf?id=0B9gIhE ... ist&num=50
<Fig. 1> Correct Image
https://docs.google.com/leaf?id=0B9gIhE ... z&hl=en_US
<Fig.2> What is actually displayed
https://docs.google.com/leaf?id=0B9gIhE ... w&hl=en_US
<Fig.3> The dpx file