[FFmpeg-devel] [PATCH 1/2 v4] avfilter: add readvitc filter

[Tobias Rapp]

On 08.04.2016 15:24, Tobias Rapp wrote:
> On 08.04.2016 14:54, Paul B Mahol wrote:
>> On 4/8/16, Tobias Rapp <t.rapp at noa-archive.com> wrote:
>>> On 08.04.2016 12:48, Carl Eugen Hoyos wrote:
>>>> Tobias Rapp <t.rapp <at> noa-archive.com> writes:
>>>>
>>>>>> AV_PIX_FMT_YUV440P? Also J variants...
>>>>>
>>>>> Good catch, I was lazy and just copied the function from vf_eq.c. The
>>>>> updated patch should contain all pixel formats with planar 8bit luma
>>>>> component.
>>>>
>>>> Instead of listing the formats, check for pix_fmts
>>>> that are 8bit and planar.
>>>
>>> That might be an even better idea. Working on v3 of the patch I noticed
>>> that YA8 (which was on the list of v2) is not planar, but NV12 and NV21
>>> (which were missing in v2) have a planar Y.
>>>
>>> Have attached version 3 of the patch which:
>>> - filters the list of all pixel formats dynamically
>>> - supports thr_b and thr_w parameters having the same value
>>> - updates the warning if thr_b == thr_w to print the parameter value
>>> instead of the internal 8-bit value
>>> - has reduced number of parentheses in CRC code
>>>
>>> Regards,
>>> Tobias
>>>
>>
>> Now, when someone adds 8bit X planar format which is not YUV it will
>> break.
>
> It depends on whether the equation "is_yuv_or_gray = (desc->flags &
> AV_PIX_FMT_FLAG_RGB) == 0)" can be made or not. The comment in
> libavutil/pixdesc.h made me assume it is safe to do so:
>
> """
> /**
>   * The pixel format contains RGB-like data (as opposed to YUV/grayscale).
>   */
> #define AV_PIX_FMT_FLAG_RGB          (1 << 5)
> """
>
> So what has more weight, the aspect of defensive programming or the cost
> of maintaining a static list?

Attached patch v4 contains the more defensive static-pixfmt-list 
approach together with the threshold changes from v3.

Regards,
Tobias
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