Determining size of data[0] in AVFrame of FFMPEG

To get the buffer size:

int avpicture_get_size(enum AVPixelFormat pix_fmt, int width, int height);

To copy pixel data:

int avpicture_layout(const AVPicture *src, enum AVPixelFormat pix_fmt,
                     int width, int height,
                     unsigned char *dest, int dest_size);