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

Reimar Döffinger Reimar.Doeffinger at gmx.de
Fri Oct 11 18:53:50 CEST 2013



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...


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