[x265] [PATCH] Fix: segmentation fault for hist-scenecut option

[Aruna Matheswaran]

Pushed to Release_3.3 and grafted the fix to default.

On Thu, Mar 19, 2020 at 11:59 AM Srikanth Kurapati <
srikanth.kurapati at multicorewareinc.com> wrote:

>  Hi Aruna,
>
> The changes in the previous patch are for segmentation
> faults occurring due to bit depth mismatch. This patch fixes
> wrong computation of plane sizes for chroma planes introduced in the
> previous changeset during code code optimization. The changes in the
> previous change set fail when ever source resolution and encoder resolution
> are different. as per the original algorithm since scd happens on x265_pic
> and not frame the chroma histogram computation should be done for source
> plane computed from source resolution and not the padded resolution in
> param structure. All histograms will be computed on the encoder bit depth
> only.
>
> On Wed, Mar 18, 2020 at 8:31 PM Aruna Matheswaran <
> aruna at multicorewareinc.com> wrote:
>
>>
>>
>> On Tue, Mar 17, 2020 at 2:48 PM <srikanth.kurapati at multicorewareinc.com>
>> wrote:
>>
>>> # HG changeset patch
>>> # User Srikanth Kurapati
>>> # Date 1584430274 -19800
>>> #      Tue Mar 17 13:01:14 2020 +0530
>>> # Node ID b7a02a40bc5d97308d41b925f9c37df414ab6ecb
>>> # Parent  b7b0de75112b8022789590640662f2fab956cfbe
>>> Fix: segmentation fault for hist-scenecut option
>>>
>>> fixes plane size calculation for chroma planes using source resolution
>>> and not
>>> padded resolution.
>>>
>>
>> Is this because you compute the luma histogram on pixel domain and chroma
>> histogram on input depth?
>> If so, do you still need the additional memory and memcpy introduced in
>> "Changeset: 12619 (96a10df63c0b) Fix: Segmentation fault for hist-scenecut
>> option in 16bpp builds." ?
>>
>>> "
>>> diff -r b7b0de75112b -r b7a02a40bc5d source/encoder/encoder.cpp
>>> --- a/source/encoder/encoder.cpp        Fri Feb 21 17:02:18 2020 +0530
>>> +++ b/source/encoder/encoder.cpp        Tue Mar 17 13:01:14 2020 +0530
>>> @@ -218,10 +218,7 @@
>>>
>>>      if (m_param->bHistBasedSceneCut)
>>>      {
>>> -        for (int i = 0; i < x265_cli_csps[m_param->internalCsp].planes;
>>> i++)
>>> -        {
>>> -            m_planeSizes[i] = (m_param->sourceWidth >>
>>> x265_cli_csps[p->internalCsp].width[i]) * (m_param->sourceHeight >>
>>> x265_cli_csps[m_param->internalCsp].height[i]);
>>> -        }
>>> +        m_planeSizes[0] = (m_param->sourceWidth >>
>>> x265_cli_csps[p->internalCsp].width[0]) * (m_param->sourceHeight >>
>>> x265_cli_csps[m_param->internalCsp].height[0]);
>>>          uint32_t pixelbytes = m_param->internalBitDepth > 8 ? 2 : 1;
>>>          m_edgePic = X265_MALLOC(pixel, m_planeSizes[0] * pixelbytes);
>>>          m_edgeHistThreshold = m_param->edgeTransitionThreshold;
>>> @@ -1605,6 +1602,14 @@
>>>          if (m_param->bHistBasedSceneCut && pic_in)
>>>          {
>>>              x265_picture *pic = (x265_picture *) pic_in;
>>> +
>>> +            if (pic->poc == 0)
>>> +            {
>>> +                /* for entire encode compute the chroma plane sizes
>>> only once */
>>> +                for (int i = 1; i <
>>> x265_cli_csps[m_param->internalCsp].planes; i++)
>>> +                    m_planeSizes[i] = (pic->width >>
>>> x265_cli_csps[m_param->internalCsp].width[i]) * (pic->height >>
>>> x265_cli_csps[m_param->internalCsp].height[i]);
>>> +            }
>>> +
>>>              if (computeHistograms(pic))
>>>              {
>>>                  double maxUVSad = 0.0, edgeSad = 0.0;
>>> _______________________________________________
>>> x265-devel mailing list
>>> x265-devel at videolan.org
>>> https://mailman.videolan.org/listinfo/x265-devel
>>>
>>
>>
>> --
>> Regards,
>> *Aruna Matheswaran,*
>> Video Codec Engineer,
>> Media & AI analytics BU,
>>
>>
>>
>> _______________________________________________
>> x265-devel mailing list
>> x265-devel at videolan.org
>> https://mailman.videolan.org/listinfo/x265-devel
>>
>
>
> --
> *With Regards,*
> *Srikanth Kurapati.*
> _______________________________________________
> x265-devel mailing list
> x265-devel at videolan.org
> https://mailman.videolan.org/listinfo/x265-devel
>


-- 
Regards,
*Aruna Matheswaran,*
Video Codec Engineer,
Media & AI analytics BU,
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