enum PixelFormat avcodec_find_best_pix_fmt(int64_t pix_fmt_mask, enum PixelFormat src_pix_fmt,
int has_alpha, int *loss_ptr);
+/**
+ * Find the best pixel format to convert to given a certain source pixel
+ * format and a selection of two destination pixel formats. When converting from
+ * one pixel format to another, information loss may occur. For example, when converting
+ * from RGB24 to GRAY, the color information will be lost. Similarly, other losses occur when
+ * converting from some formats to other formats. avcodec_find_best_pix_fmt2() selects which of
+ * the given pixel formats should be used to suffer the least amount of loss.
+ *
+ * If one of the destination formats is PIX_FMT_NONE the other pixel format (if valid) will be
+ * returned.
+ *
+ * @code
+ * src_pix_fmt = PIX_FMT_YUV420P;
+ * dst_pix_fmt1= PIX_FMT_RGB24;
+ * dst_pix_fmt2= PIX_FMT_GRAY8;
+ * dst_pix_fmt3= PIX_FMT_RGB8;
+ * loss= FF_LOSS_CHROMA; // don't care about chroma loss, so chroma loss will be ignored.
+ * dst_pix_fmt = avcodec_find_best_pix_fmt2(dst_pix_fmt1, dst_pix_fmt2, src_pix_fmt, alpha, &loss);
+ * dst_pix_fmt = avcodec_find_best_pix_fmt2(dst_pix_fmt, dst_pix_fmt3, src_pix_fmt, alpha, &loss);
+ * @endcode
+ *
+ * @param[in] dst_pix_fmt1 One of the two destination pixel formats to choose from
+ * @param[in] dst_pix_fmt2 The other of the two destination pixel formats to choose from
+ * @param[in] src_pix_fmt Source pixel format
+ * @param[in] has_alpha Whether the source pixel format alpha channel is used.
+ * @param[in, out] loss_ptr Combination of loss flags. In: selects which of the losses to ignore, i.e.
+ * NULL or value of zero means we care about all losses. Out: the loss
+ * that occurs when converting from src to selected dst pixel format.
+ * @return The best pixel format to convert to or -1 if none was found.
+ */
+enum PixelFormat avcodec_find_best_pix_fmt2(enum PixelFormat dst_pix_fmt1, enum PixelFormat dst_pix_fmt2,
+ enum PixelFormat src_pix_fmt, int has_alpha, int *loss_ptr);
+
#define FF_ALPHA_TRANSP 0x0001 /* image has some totally transparent pixels */
#define FF_ALPHA_SEMI_TRANSP 0x0002 /* image has some transparent pixels */
}
enum PixelFormat avcodec_find_best_pix_fmt(int64_t pix_fmt_mask, enum PixelFormat src_pix_fmt,
- int has_alpha, int *loss_ptr)
+ int has_alpha, int *loss_ptr)
{
enum PixelFormat dst_pix_fmt;
- int loss_mask, i;
+ int i;
+
+ if (loss_ptr) /* all losses count (for backward compatibility) */
+ *loss_ptr = 0;
+
+ dst_pix_fmt = PIX_FMT_NONE; /* so first iteration doesn't have to be treated special */
+ for(i = 0; i< FFMIN(PIX_FMT_NB, 64); i++){
+ if (pix_fmt_mask & (1ULL << i))
+ dst_pix_fmt = avcodec_find_best_pix_fmt2(dst_pix_fmt, i, src_pix_fmt, has_alpha, loss_ptr);
+ }
+ return dst_pix_fmt;
+}
+
+enum PixelFormat avcodec_find_best_pix_fmt2(enum PixelFormat dst_pix_fmt1, enum PixelFormat dst_pix_fmt2,
+ enum PixelFormat src_pix_fmt, int has_alpha, int *loss_ptr)
+{
+ enum PixelFormat dst_pix_fmt;
+ int loss1, loss2, loss_order1, loss_order2, i, loss_mask;
static const int loss_mask_order[] = {
~0, /* no loss first */
~FF_LOSS_ALPHA,
~(FF_LOSS_COLORSPACE | FF_LOSS_RESOLUTION),
~FF_LOSS_COLORQUANT,
~FF_LOSS_DEPTH,
+ ~(FF_LOSS_RESOLUTION | FF_LOSS_DEPTH | FF_LOSS_COLORSPACE | FF_LOSS_ALPHA |
+ FF_LOSS_COLORQUANT | FF_LOSS_CHROMA),
0,
};
+ loss_mask= loss_ptr?~*loss_ptr:~0; /* use loss mask if provided */
+ dst_pix_fmt = PIX_FMT_NONE;
+ loss1 = avcodec_get_pix_fmt_loss(dst_pix_fmt1, src_pix_fmt, has_alpha) & loss_mask;
+ loss2 = avcodec_get_pix_fmt_loss(dst_pix_fmt2, src_pix_fmt, has_alpha) & loss_mask;
+
/* try with successive loss */
- i = 0;
- for(;;) {
- loss_mask = loss_mask_order[i++];
- dst_pix_fmt = avcodec_find_best_pix_fmt1(pix_fmt_mask, src_pix_fmt,
- has_alpha, loss_mask);
- if (dst_pix_fmt >= 0)
- goto found;
- if (loss_mask == 0)
- break;
+ for(i = 0;loss_mask_order[i] != 0 && dst_pix_fmt == PIX_FMT_NONE;i++) {
+ loss_order1 = loss1 & loss_mask_order[i];
+ loss_order2 = loss2 & loss_mask_order[i];
+
+ if (loss_order1 == 0 && loss_order2 == 0){ /* use format with smallest depth */
+ dst_pix_fmt = avg_bits_per_pixel(dst_pix_fmt2) < avg_bits_per_pixel(dst_pix_fmt1) ? dst_pix_fmt2 : dst_pix_fmt1;
+ } else if (loss_order1 == 0 || loss_order2 == 0) { /* use format with no loss */
+ dst_pix_fmt = loss_order2 ? dst_pix_fmt1 : dst_pix_fmt2;
+ }
}
- return PIX_FMT_NONE;
- found:
+
if (loss_ptr)
*loss_ptr = avcodec_get_pix_fmt_loss(dst_pix_fmt, src_pix_fmt, has_alpha);
return dst_pix_fmt;