[FFmpeg-devel] openjpeg: 12bits JP2 file (16bits support + patch)

[Baptiste Coudurier]

Hi Jai,

Jai Menon wrote:
> On Wed, Feb 11, 2009 at 7:20 PM, Mathieu Malaterre
> <mathieu.malaterre at gmail.com> wrote:
>> On Mon, Feb 9, 2009 at 2:38 PM, Mathieu Malaterre
>> <mathieu.malaterre at gmail.com> wrote:
>>> On Mon, Feb 9, 2009 at 2:36 PM, Mathieu Malaterre
>>> <mathieu.malaterre at gmail.com> wrote:
>>>> Jay,
>>>>
>>>>  Could you have a look at:
>>>>
>>>> http://jpeg.sourceforge.net/jpeg2000/dental_12bits.jp2
>>>>
>>>>  Does your implementation handle 12bits data ? I am seeing some minor
>>>> difference compared to using openjpeg directly.
>>>>
>>> Sorry forgot the cmd line:
>>>
>>> ./ffmpeg  -f image2  -vcodec libopenjpeg -i dental_12bits.jp2 -f
>>> image2 -pix_fmt gray16be -vcodec pgm dental_12bits.pgm
>> Jai,
>>
>>  I think with this patch I can get 16bits working. I still do not
>> understand what is the 'adjust' parameter.
> 
> Sorry for the delay. The adjust parameter is there to trivially throw away the
> lsbs which won't fit in a single byte. If you want, I could add 16bit grayscale
> support but the general solution would be to add the required pixfmts
> to avutil.h.
> And also a converter which allows us to scale these > 8bits per component down.
> The only reason your patch works is because there is a converter defined. See
> convert_table in lavc/imgconvert.c.

Btw, I noticed ffmpeg crashed on Speedway.mj2 which can be found on
openjpeg website. Does it support mj2 yet ?

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