[FFmpeg-devel] [PATCH] exr: piz decompression

Reimar Döffinger Reimar.Doeffinger at gmx.de
Fri Oct 11 20:08:25 CEST 2013

On 11.10.2013, at 18:58, Paul B Mahol <onemda at gmail.com> wrote:
> On 10/11/13, Reimar Doeffinger <Reimar.Doeffinger at gmx.de> wrote:
>> On 10.10.2013, at 12:48, Paul B Mahol <onemda at gmail.com> wrote:
>>> On 10/10/13, Reimar Doeffinger <Reimar.Doeffinger at gmx.de> wrote:
>>>> On 09.10.2013, at 15:22, Paul B Mahol <onemda at gmail.com> wrote:
>>>>> On 8/11/13, Reimar Doeffinger <Reimar.Doeffinger at gmx.de> wrote:
>>>>>> On Sun, Aug 11, 2013 at 04:23:54PM +0200, Piotr Bandurski wrote:
>>>>>>> Hi,
>>>>>>>>> Signed-off-by: Paul B Mahol <onemda at gmail.com>
>>>>>>>> ---
>>>>>>>> libavcodec/exr.c | 477
>>>>>>>> +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>>>>>>>> 1 file changed, 477 insertions(+)
>>>>>>>> diff --git a/libavcodec/exr.c b/libavcodec/exr.c
>>>>>>>> index 7e9e68c..a65e6ba 100644
>>>>>>>> --- a/libavcodec/exr.c
>>>>>>>> +++ b/libavcodec/exr.c
>>>>>>> What is the status of this patch?
>>>>>> I suspect it is kind of waiting for someone to figure out if this
>>>>>> is rather ordinary huffman/VLC coding as I guessed and thus should
>>>>>> be using the functions we have for that instead of reimplementing it
>>>>>> or if I'm completely off...
>>>>> I will apply this unless someone shows this really can be used by
>>>>> existing
>>>>> code.
>>>> What needs to be shown? The generic vlc code should handle basically any
>>>> kind of variable length code to symbol conversion.
>>>> I think that is what the code does, though I don't fully understand it -
>>>> assuming you understand the code that should answer whether it can be
>>>> used?
>>>> Whether the huffman code could be reused is more tricky, and I don't
>>>> really
>>>> care about it, it just might have been one way to make more clear what
>>>> kind
>>>> of concepts this codec uses and how it differs from how it is done
>>>> commonly.
>>> Looks like neither you nor me can do it so I will apply this as is
>>> (with additional
>>> issues fixed).
>> I very much expect I could, though I don't care one bit about this feature,
>> so avoiding messy code duplication is the only reason for me to do it.
>> Is there a good specification of the format? I definitely don't want to do
>> it if I have to reverse-engineer your code into a specification first...
> There is no specification for this codec(its is based on PIZ image though),
> all documents points to take look at OpenEXR source code.

Oh well. I guess go ahead then.
Maybe I'll find time to try to make it reuse the VLC code, but it will be some time.
Litlle value in letting the patch rot. Of course I'd welcome anyone looking into it.

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