[Libav-user] Calculating the number of bytes in YUV planes

[Anton Shekhovtsov]

2018-04-23 8:16 GMT+03:00 Sampsa Riikonen <sampsa.riikonen at iki.fi>:

> Dear List,
>
> I am decoding H264 into YUV and using the YUV bitmaps in a custom
> application.
>
> For av pixel formats
>
> AV_PIX_FMT_YUV420P
>
> AV_PIX_FMT_YUVJ420P
>
> I calculate the number of bytes in each plane like this (av_frame is
> AVFrame*):
>
> y_size =(GLsizei)( (av_frame->height)*(av_frame->linesize[0]) );
> u_size =(GLsizei)( (av_frame->height/2)*(av_frame->linesize[1]) );
> v_size =(GLsizei)( (av_frame->height/2)*(av_frame->linesize[2]) );
>
> Question 1: Is there a more "standard" way of doing this?  Here I am using
> "outside" information by assuming that "height/2".  Can I get the number of
> bytes in each plane (safely) somewhere from the AVCodecContext or AVFrame
> structures directly?
>
> Then, accessing the data itself:
>
> av_frame->data[0] has y_size bytes
>
> av_frame->data[1] has u_size bytes
>
> av_frame->data[2] has v_size bytes
>
> Question 2: Can I assume that data[0]..data[2] is a continuous block of
> memory?
>
> Regards,
>
> Sampsa
>
>
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>

Take a look at av_image_fill_arrays and other imgutils.h functions.
Also av_pix_fmt_desc_get.
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