[FFmpeg-devel] [PATCH] avcodec/pngdec: support alpha blending for palette apng
Paul B Mahol
onemda at gmail.com
Sat Mar 5 20:10:59 EET 2022
Update clock test, as PAL8 apngs are now decoded as RGBA.
Signed-off-by: Paul B Mahol <onemda at gmail.com>
---
libavcodec/pngdec.c | 61 +++++++++++++++--------------
tests/ref/fate/apng-clock | 80 +++++++++++++++++++--------------------
2 files changed, 72 insertions(+), 69 deletions(-)
diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c
index 39bb652f67..a335a29b08 100644
--- a/libavcodec/pngdec.c
+++ b/libavcodec/pngdec.c
@@ -677,7 +677,7 @@ static int decode_idat_chunk(AVCodecContext *avctx, PNGDecContext *s,
avctx->pix_fmt = AV_PIX_FMT_RGBA64BE;
} else if ((s->bits_per_pixel == 1 || s->bits_per_pixel == 2 || s->bits_per_pixel == 4 || s->bits_per_pixel == 8) &&
s->color_type == PNG_COLOR_TYPE_PALETTE) {
- avctx->pix_fmt = AV_PIX_FMT_PAL8;
+ avctx->pix_fmt = avctx->codec_id == AV_CODEC_ID_APNG ? AV_PIX_FMT_RGBA : AV_PIX_FMT_PAL8;
} else if (s->bit_depth == 1 && s->bits_per_pixel == 1 && avctx->codec_id != AV_CODEC_ID_APNG) {
avctx->pix_fmt = AV_PIX_FMT_MONOBLACK;
} else if (s->bit_depth == 8 &&
@@ -1022,7 +1022,6 @@ static int decode_fctl_chunk(AVCodecContext *avctx, PNGDecContext *s,
if (blend_op == APNG_BLEND_OP_OVER && !s->has_trns && (
avctx->pix_fmt == AV_PIX_FMT_RGB24 ||
avctx->pix_fmt == AV_PIX_FMT_RGB48BE ||
- avctx->pix_fmt == AV_PIX_FMT_PAL8 ||
avctx->pix_fmt == AV_PIX_FMT_GRAY8 ||
avctx->pix_fmt == AV_PIX_FMT_GRAY16BE ||
avctx->pix_fmt == AV_PIX_FMT_MONOBLACK
@@ -1070,13 +1069,13 @@ static int handle_p_frame_apng(AVCodecContext *avctx, PNGDecContext *s,
ptrdiff_t dst_stride = p->linesize[0];
const uint8_t *src = s->last_picture.f->data[0];
ptrdiff_t src_stride = s->last_picture.f->linesize[0];
+ const int bpp = s->color_type == PNG_COLOR_TYPE_PALETTE ? 4 : s->bpp;
size_t x, y;
if (s->blend_op == APNG_BLEND_OP_OVER &&
avctx->pix_fmt != AV_PIX_FMT_RGBA &&
- avctx->pix_fmt != AV_PIX_FMT_GRAY8A &&
- avctx->pix_fmt != AV_PIX_FMT_PAL8) {
+ avctx->pix_fmt != AV_PIX_FMT_GRAY8A) {
avpriv_request_sample(avctx, "Blending with pixel format %s",
av_get_pix_fmt_name(avctx->pix_fmt));
return AVERROR_PATCHWELCOME;
@@ -1095,7 +1094,7 @@ static int handle_p_frame_apng(AVCodecContext *avctx, PNGDecContext *s,
for (y = s->last_y_offset; y < s->last_y_offset + s->last_h; y++) {
memset(s->background_buf + src_stride * y +
- s->bpp * s->last_x_offset, 0, s->bpp * s->last_w);
+ bpp * s->last_x_offset, 0, bpp * s->last_w);
}
src = s->background_buf;
@@ -1103,22 +1102,22 @@ static int handle_p_frame_apng(AVCodecContext *avctx, PNGDecContext *s,
// copy unchanged rectangles from the last frame
for (y = 0; y < s->y_offset; y++)
- memcpy(dst + y * dst_stride, src + y * src_stride, p->width * s->bpp);
+ memcpy(dst + y * dst_stride, src + y * src_stride, p->width * bpp);
for (y = s->y_offset; y < s->y_offset + s->cur_h; y++) {
- memcpy(dst + y * dst_stride, src + y * src_stride, s->x_offset * s->bpp);
- memcpy(dst + y * dst_stride + (s->x_offset + s->cur_w) * s->bpp,
- src + y * src_stride + (s->x_offset + s->cur_w) * s->bpp,
- (p->width - s->cur_w - s->x_offset) * s->bpp);
+ memcpy(dst + y * dst_stride, src + y * src_stride, s->x_offset * bpp);
+ memcpy(dst + y * dst_stride + (s->x_offset + s->cur_w) * bpp,
+ src + y * src_stride + (s->x_offset + s->cur_w) * bpp,
+ (p->width - s->cur_w - s->x_offset) * bpp);
}
for (y = s->y_offset + s->cur_h; y < p->height; y++)
- memcpy(dst + y * dst_stride, src + y * src_stride, p->width * s->bpp);
+ memcpy(dst + y * dst_stride, src + y * src_stride, p->width * bpp);
if (s->blend_op == APNG_BLEND_OP_OVER) {
// Perform blending
for (y = s->y_offset; y < s->y_offset + s->cur_h; ++y) {
- uint8_t *foreground = dst + dst_stride * y + s->bpp * s->x_offset;
- const uint8_t *background = src + src_stride * y + s->bpp * s->x_offset;
- for (x = s->x_offset; x < s->x_offset + s->cur_w; ++x, foreground += s->bpp, background += s->bpp) {
+ uint8_t *foreground = dst + dst_stride * y + bpp * s->x_offset;
+ const uint8_t *background = src + src_stride * y + bpp * s->x_offset;
+ for (x = s->x_offset; x < s->x_offset + s->cur_w; ++x, foreground += bpp, background += bpp) {
size_t b;
uint8_t foreground_alpha, background_alpha, output_alpha;
uint8_t output[10];
@@ -1137,32 +1136,21 @@ static int handle_p_frame_apng(AVCodecContext *avctx, PNGDecContext *s,
foreground_alpha = foreground[1];
background_alpha = background[1];
break;
-
- case AV_PIX_FMT_PAL8:
- foreground_alpha = s->palette[foreground[0]] >> 24;
- background_alpha = s->palette[background[0]] >> 24;
- break;
}
if (foreground_alpha == 255)
continue;
if (foreground_alpha == 0) {
- memcpy(foreground, background, s->bpp);
- continue;
- }
-
- if (avctx->pix_fmt == AV_PIX_FMT_PAL8) {
- // TODO: Alpha blending with PAL8 will likely need the entire image converted over to RGBA first
- avpriv_request_sample(avctx, "Alpha blending palette samples");
+ memcpy(foreground, background, bpp);
continue;
}
output_alpha = foreground_alpha + FAST_DIV255((255 - foreground_alpha) * background_alpha);
- av_assert0(s->bpp <= 10);
+ av_assert0(bpp <= 10);
- for (b = 0; b < s->bpp - 1; ++b) {
+ for (b = 0; b < bpp - 1; ++b) {
if (output_alpha == 0) {
output[b] = 0;
} else if (background_alpha == 255) {
@@ -1172,7 +1160,7 @@ static int handle_p_frame_apng(AVCodecContext *avctx, PNGDecContext *s,
}
}
output[b] = output_alpha;
- memcpy(foreground, output, s->bpp);
+ memcpy(foreground, output, bpp);
}
}
}
@@ -1368,6 +1356,21 @@ exit_loop:
if (s->bits_per_pixel <= 4)
handle_small_bpp(s, p);
+ if (s->color_type == PNG_COLOR_TYPE_PALETTE && avctx->codec_id == AV_CODEC_ID_APNG) {
+ for (int y = 0; y < s->height; y++) {
+ uint8_t *row = &p->data[0][p->linesize[0] * y];
+
+ for (int x = s->width - 1; x >= 0; x--) {
+ const uint8_t idx = row[x];
+
+ row[4*x+2] = s->palette[idx] & 0xFF;
+ row[4*x+1] = (s->palette[idx] >> 8 ) & 0xFF;
+ row[4*x+0] = (s->palette[idx] >> 16) & 0xFF;
+ row[4*x+3] = s->palette[idx] >> 24;
+ }
+ }
+ }
+
/* apply transparency if needed */
if (s->has_trns && s->color_type != PNG_COLOR_TYPE_PALETTE) {
size_t byte_depth = s->bit_depth > 8 ? 2 : 1;
diff --git a/tests/ref/fate/apng-clock b/tests/ref/fate/apng-clock
index c0480fd4e6..26afc94c19 100644
--- a/tests/ref/fate/apng-clock
+++ b/tests/ref/fate/apng-clock
@@ -3,43 +3,43 @@
#codec_id 0: rawvideo
#dimensions 0: 150x150
#sar 0: 0/1
-0, 0, 0, 1, 23524, 0xf09caaa1
-0, 1, 1, 1, 23524, 0x1a329f21
-0, 2, 2, 1, 23524, 0x9b0ca017
-0, 3, 3, 1, 23524, 0x73b09deb
-0, 4, 4, 1, 23524, 0x23039f49
-0, 5, 5, 1, 23524, 0x58869e7b
-0, 6, 6, 1, 23524, 0xc26397d2
-0, 7, 7, 1, 23524, 0xe07f7d87
-0, 8, 8, 1, 23524, 0x619a82ba
-0, 9, 9, 1, 23524, 0x696c9757
-0, 10, 10, 1, 23524, 0x7303a4a6
-0, 11, 11, 1, 23524, 0x1e149aee
-0, 12, 12, 1, 23524, 0x78dd97e0
-0, 13, 13, 1, 23524, 0xad8092d3
-0, 14, 14, 1, 23524, 0x27c090b4
-0, 15, 15, 1, 23524, 0x904c97be
-0, 16, 16, 1, 23524, 0x54d29b9e
-0, 17, 17, 1, 23524, 0x57689bfa
-0, 18, 18, 1, 23524, 0x2772a00e
-0, 19, 19, 1, 23524, 0x6a769ef6
-0, 20, 20, 1, 23524, 0x94d8aad5
-0, 21, 21, 1, 23524, 0x52f79ec4
-0, 22, 22, 1, 23524, 0x99ee9fbc
-0, 23, 23, 1, 23524, 0xbd6a9e4d
-0, 24, 24, 1, 23524, 0xaf4aa1cf
-0, 25, 25, 1, 23524, 0xdb929f98
-0, 26, 26, 1, 23524, 0x9e189a6f
-0, 27, 27, 1, 23524, 0x3ffb9410
-0, 28, 28, 1, 23524, 0x6fc9917d
-0, 29, 29, 1, 23524, 0xe43e94ca
-0, 30, 30, 1, 23524, 0x03b6a24f
-0, 31, 31, 1, 23524, 0xc54f99b3
-0, 32, 32, 1, 23524, 0x4b9a9748
-0, 33, 33, 1, 23524, 0x25a19003
-0, 34, 34, 1, 23524, 0x2b9d77cc
-0, 35, 35, 1, 23524, 0x4a5a9217
-0, 36, 36, 1, 23524, 0x241b9a7c
-0, 37, 37, 1, 23524, 0xc9d39b38
-0, 38, 38, 1, 23524, 0xcca69f30
-0, 39, 39, 1, 23524, 0xe50f9ec9
+0, 0, 0, 1, 90000, 0x11af5588
+0, 1, 1, 1, 90000, 0x528c2eb8
+0, 2, 2, 1, 90000, 0xebae2d82
+0, 3, 3, 1, 90000, 0xf57951ef
+0, 4, 4, 1, 90000, 0xc2a84734
+0, 5, 5, 1, 90000, 0x2dd74265
+0, 6, 6, 1, 90000, 0x5a6980cb
+0, 7, 7, 1, 90000, 0x519373e4
+0, 8, 8, 1, 90000, 0xdca835fb
+0, 9, 9, 1, 90000, 0xc8a46d5e
+0, 10, 10, 1, 90000, 0xa01a72e3
+0, 11, 11, 1, 90000, 0xacd751fa
+0, 12, 12, 1, 90000, 0x464b6d39
+0, 13, 13, 1, 90000, 0x56f1b22c
+0, 14, 14, 1, 90000, 0x0595a6bb
+0, 15, 15, 1, 90000, 0xb9418cdc
+0, 16, 16, 1, 90000, 0x8b2b7bcf
+0, 17, 17, 1, 90000, 0x1a026aaf
+0, 18, 18, 1, 90000, 0x25443715
+0, 19, 19, 1, 90000, 0x3d9231cd
+0, 20, 20, 1, 90000, 0xfef153a8
+0, 21, 21, 1, 90000, 0x6a7c2e7b
+0, 22, 22, 1, 90000, 0x1fe92cda
+0, 23, 23, 1, 90000, 0x30554ff8
+0, 24, 24, 1, 90000, 0x57e544d9
+0, 25, 25, 1, 90000, 0x4c2d3b69
+0, 26, 26, 1, 90000, 0x22c26e0c
+0, 27, 27, 1, 90000, 0x254bb498
+0, 28, 28, 1, 90000, 0xcd02a4ac
+0, 29, 29, 1, 90000, 0x54447feb
+0, 30, 30, 1, 90000, 0x9dc87b6e
+0, 31, 31, 1, 90000, 0xfb49553b
+0, 32, 32, 1, 90000, 0x05316fbe
+0, 33, 33, 1, 90000, 0xd796da15
+0, 34, 34, 1, 90000, 0x36064111
+0, 35, 35, 1, 90000, 0x470cb58e
+0, 36, 36, 1, 90000, 0xf0ba8054
+0, 37, 37, 1, 90000, 0x3f496ff8
+0, 38, 38, 1, 90000, 0xe3a43cff
+0, 39, 39, 1, 90000, 0xacdd36ce
--
2.33.0
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