[gdal-dev] JPEG format.

[Even Rouault]

Le Wednesday 29 July 2009 20:46:47 Martin Chapman, vous avez écrit :
> Good question.  I imagine it is extra work for Frank that falls low on the
> priority list. :)

Another problem is that if you want to create a big raster, it might not hold 
entirely into RAM (a JPEG file  uncompressed into RAM can use up to 
65000x65000x3=12 GB). The general GDAL policy is to minimize the use of RAM.

>
> Martin
>
> -----Original Message-----
> From: Belaid MOA <belaid_moa at hotmail.com>
>
> Date: Wed, 29 Jul 2009 18:46:28
> To: <chapmanm at pixia.com>; <gdal-dev at lists.osgeo.org>
> Subject: RE: [gdal-dev] JPEG format.
>
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> That's excellent to know! Thanks a lot Martin. Instead of getting
> segfault,
> I could use that to exist peacefully in case the driver does support the
> Create() function.
>
> Just of out of curiosity, why JPEG driver does not have the create function
> and only supports CreateCopy()? The Create() function could be easily
> implemented using MEM and CreateCopy(); instead of relying on the user to
> do this every time a JPEG driver is used.
>
> With best regards.
> ~Belaid.
> From: chapmanm at pixia.com
> To: belaid_moa at hotmail.com; gdal-dev at lists.osgeo.org
> Subject: RE: [gdal-dev] JPEG format.
> Date: Wed, 29 Jul 2009 11:56:04 -0600
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> Use:
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> if
> (!pDriver->TestCapability(ODrCCreateDataSource))
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> to
> test create capabilties of the driver.
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> I
> think jpeg driver only supports CreateCopy().
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> You
> could use the Memory dataset to create a different size dataset and then
> use the jpeg driver to save it to disk.
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>
> Martin
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>
> From:
> gdal-dev-bounces at lists.osgeo.org [mailto:gdal-dev-bounces at lists.osgeo.org]
> On Behalf Of Belaid MOA
>
> Sent: Wednesday, July 29, 2009 11:45 AM
>
> To: gdal-dev at lists.osgeo.org
>
> Subject: [gdal-dev] JPEG format.
>
>
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> Hi Everyone,
>
>   When I try to use GDALCreate() on the JPEG driver, I got the following
> error: "GDALDriver::Create() ... no create method implemented for this
> format."
>
>   Does is this mean that JPEG driver does not have its GDALCreate()
> function implemented? Any example on how to use JPEG driver is appreciated.
>
>
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>   As always, any help on this is very appreciated.
>
>
>
> With best regards.
>
> ~Belaid
>
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>
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