* see avcodec_align_dimensions2(). Some filters and swscale can read
* up to 16 bytes beyond the planes, if these filters are to be used,
* then 16 extra bytes must be allocated.
+ *
+ * NOTE: Except for hwaccel formats, pointers not needed by the format
+ * MUST be set to NULL.
*/
uint8_t *data[AV_NUM_DATA_POINTERS];