[Libav-user] 4k video decoding planner data

[Ankush Wadke]

Thanks for the reply Harry.
And yes it has something to do with the offset of U and V planes but it
works perfectly fine for a FHD stream i.e. 1920x1080 but dosent seem to for
a 3840x2160 stream. Does planer data require alignment to be considered?

On Wed, Jul 27, 2016 at 7:51 PM, Harry <Harry at gps-laptimer.de> wrote:

> Green borders are a wrong offset / starting address for the UV planes.
>
> Harry
>
> Sent from my smartphone
>
> On 27 Jul 2016, at 11:47, Ankush Wadke <wadkes93 at gmail.com> wrote:
>
> Hi everybody,
>     I am stuck with a problem to which I am not able to figure out what
> exactly is wrong.
>     I am decoding a 4k video which gives me a YUV420P output frame. In
> order to convert it to UYVY I wrote a piece of code. which works fine for
> first frame, then second frame has a small green line and the third frame
> has the colors totally displaced. I am getting the correct frames sometimes
> but i am not able to figure out what is wrong with the other frames.
>     It would be really helpful if someone would point me to something tat
> would help.
>
> hers the code i am using for conversion,
>
> void Convert_yuv420_to_yuv422(const AVFrame &videoBuffer, uint8_t *
> opBuffer, const int const &Width,  const int const &Height)
> {
> uint8_t  *buffer_uyvy_1strow = opBuffer,
>                     *buffer_uyvy_2ndrow = opBuffer+(2*Width);
>
> uint8_t *y_1strow = videoBuffer.data[0],
> *y_2ndrow = videoBuffer.data[0]+Width;
>
> uint8_t * u_ptr = videoBuffer.data[1];
> uint8_t * v_ptr = videoBuffer.data[2];
>
> for (unsigned int i_conv_ht =0; i_conv_ht<Height;i_conv_ht+=2) {
> for (unsigned int i_conv_wt =0; i_conv_wt<Width;i_conv_wt+=2) {
> *buffer_uyvy_1strow++ = *u_ptr;
> *buffer_uyvy_1strow++ = *y_1strow++;
> *buffer_uyvy_1strow++ = *v_ptr;
> *buffer_uyvy_1strow++ = *y_1strow++;
>
> *buffer_uyvy_2ndrow++ = *u_ptr;
> *buffer_uyvy_2ndrow++ = *y_2ndrow++;
> *buffer_uyvy_2ndrow++ = *v_ptr;
> *buffer_uyvy_2ndrow++ = *y_2ndrow++;
>
> ++u_ptr;
> ++v_ptr;
> }
> y_1strow += Width;
> y_2ndrow += Width;
>
> buffer_uyvy_1strow += FFALIGN((2*Width),1);
> buffer_uyvy_2ndrow += FFALIGN((2*Width),1);
> }
> }
>
> Regards,
> Ankush
>
>    -
>       -
>
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>


-- 


*Ankush Wadke*
Mob: 9673898604
Email: wadkes93 at gmail.com

   -
      - in.linkedin.com/pub/ankush-wadke/36/868/981/
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