[FFmpeg-cvslog] avcodec/pngdec: create a function to handle small (<=4) bits per pixel values.
Benoit Fouet
git at videolan.org
Fri Nov 14 17:19:46 CET 2014
ffmpeg | branch: master | Benoit Fouet <benoit.fouet at free.fr> | Fri Nov 14 10:17:38 2014 +0100| [8cab24df0780ccd8acf5f9e9554b2be9459e8be2] | committer: Michael Niedermayer
avcodec/pngdec: create a function to handle small (<=4) bits per pixel values.
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=8cab24df0780ccd8acf5f9e9554b2be9459e8be2
---
libavcodec/pngdec.c | 144 +++++++++++++++++++++++++++------------------------
1 file changed, 75 insertions(+), 69 deletions(-)
diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c
index 2f22ade..d3c8ef9 100644
--- a/libavcodec/pngdec.c
+++ b/libavcodec/pngdec.c
@@ -713,6 +713,79 @@ static int decode_trns_chunk(AVCodecContext *avctx, PNGDecContext *s,
return 0;
}
+static void handle_small_bpp(PNGDecContext *s, AVFrame *p)
+{
+ if (s->bits_per_pixel == 1 && s->color_type == PNG_COLOR_TYPE_PALETTE) {
+ int i, j, k;
+ uint8_t *pd = p->data[0];
+ for (j = 0; j < s->height; j++) {
+ i = s->width / 8;
+ for (k = 7; k >= 1; k--)
+ if ((s->width&7) >= k)
+ pd[8*i + k - 1] = (pd[i]>>8-k) & 1;
+ for (i--; i >= 0; i--) {
+ pd[8*i + 7]= pd[i] & 1;
+ pd[8*i + 6]= (pd[i]>>1) & 1;
+ pd[8*i + 5]= (pd[i]>>2) & 1;
+ pd[8*i + 4]= (pd[i]>>3) & 1;
+ pd[8*i + 3]= (pd[i]>>4) & 1;
+ pd[8*i + 2]= (pd[i]>>5) & 1;
+ pd[8*i + 1]= (pd[i]>>6) & 1;
+ pd[8*i + 0]= pd[i]>>7;
+ }
+ pd += s->image_linesize;
+ }
+ } else if (s->bits_per_pixel == 2) {
+ int i, j;
+ uint8_t *pd = p->data[0];
+ for (j = 0; j < s->height; j++) {
+ i = s->width / 4;
+ if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
+ if ((s->width&3) >= 3) pd[4*i + 2]= (pd[i] >> 2) & 3;
+ if ((s->width&3) >= 2) pd[4*i + 1]= (pd[i] >> 4) & 3;
+ if ((s->width&3) >= 1) pd[4*i + 0]= pd[i] >> 6;
+ for (i--; i >= 0; i--) {
+ pd[4*i + 3]= pd[i] & 3;
+ pd[4*i + 2]= (pd[i]>>2) & 3;
+ pd[4*i + 1]= (pd[i]>>4) & 3;
+ pd[4*i + 0]= pd[i]>>6;
+ }
+ } else {
+ if ((s->width&3) >= 3) pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
+ if ((s->width&3) >= 2) pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
+ if ((s->width&3) >= 1) pd[4*i + 0]= ( pd[i]>>6 )*0x55;
+ for (i--; i >= 0; i--) {
+ pd[4*i + 3]= ( pd[i] & 3)*0x55;
+ pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
+ pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
+ pd[4*i + 0]= ( pd[i]>>6 )*0x55;
+ }
+ }
+ pd += s->image_linesize;
+ }
+ } else if (s->bits_per_pixel == 4) {
+ int i, j;
+ uint8_t *pd = p->data[0];
+ for (j = 0; j < s->height; j++) {
+ i = s->width/2;
+ if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
+ if (s->width&1) pd[2*i+0]= pd[i]>>4;
+ for (i--; i >= 0; i--) {
+ pd[2*i + 1] = pd[i] & 15;
+ pd[2*i + 0] = pd[i] >> 4;
+ }
+ } else {
+ if (s->width & 1) pd[2*i + 0]= (pd[i] >> 4) * 0x11;
+ for (i--; i >= 0; i--) {
+ pd[2*i + 1] = (pd[i] & 15) * 0x11;
+ pd[2*i + 0] = (pd[i] >> 4) * 0x11;
+ }
+ }
+ pd += s->image_linesize;
+ }
+ }
+}
+
static int decode_frame_png(AVCodecContext *avctx,
void *data, int *got_frame,
AVPacket *avpkt)
@@ -820,75 +893,8 @@ skip_tag:
}
exit_loop:
- if (s->bits_per_pixel == 1 && s->color_type == PNG_COLOR_TYPE_PALETTE) {
- int i, j, k;
- uint8_t *pd = p->data[0];
- for (j = 0; j < s->height; j++) {
- i = s->width / 8;
- for (k = 7; k >= 1; k--)
- if ((s->width&7) >= k)
- pd[8*i + k - 1] = (pd[i]>>8-k) & 1;
- for (i--; i >= 0; i--) {
- pd[8*i + 7]= pd[i] & 1;
- pd[8*i + 6]= (pd[i]>>1) & 1;
- pd[8*i + 5]= (pd[i]>>2) & 1;
- pd[8*i + 4]= (pd[i]>>3) & 1;
- pd[8*i + 3]= (pd[i]>>4) & 1;
- pd[8*i + 2]= (pd[i]>>5) & 1;
- pd[8*i + 1]= (pd[i]>>6) & 1;
- pd[8*i + 0]= pd[i]>>7;
- }
- pd += s->image_linesize;
- }
- } else if (s->bits_per_pixel == 2) {
- int i, j;
- uint8_t *pd = p->data[0];
- for (j = 0; j < s->height; j++) {
- i = s->width / 4;
- if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
- if ((s->width&3) >= 3) pd[4*i + 2]= (pd[i] >> 2) & 3;
- if ((s->width&3) >= 2) pd[4*i + 1]= (pd[i] >> 4) & 3;
- if ((s->width&3) >= 1) pd[4*i + 0]= pd[i] >> 6;
- for (i--; i >= 0; i--) {
- pd[4*i + 3]= pd[i] & 3;
- pd[4*i + 2]= (pd[i]>>2) & 3;
- pd[4*i + 1]= (pd[i]>>4) & 3;
- pd[4*i + 0]= pd[i]>>6;
- }
- } else {
- if ((s->width&3) >= 3) pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
- if ((s->width&3) >= 2) pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
- if ((s->width&3) >= 1) pd[4*i + 0]= ( pd[i]>>6 )*0x55;
- for (i--; i >= 0; i--) {
- pd[4*i + 3]= ( pd[i] & 3)*0x55;
- pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
- pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
- pd[4*i + 0]= ( pd[i]>>6 )*0x55;
- }
- }
- pd += s->image_linesize;
- }
- } else if (s->bits_per_pixel == 4) {
- int i, j;
- uint8_t *pd = p->data[0];
- for (j = 0; j < s->height; j++) {
- i = s->width/2;
- if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
- if (s->width&1) pd[2*i+0]= pd[i]>>4;
- for (i--; i >= 0; i--) {
- pd[2*i + 1] = pd[i] & 15;
- pd[2*i + 0] = pd[i] >> 4;
- }
- } else {
- if (s->width & 1) pd[2*i + 0]= (pd[i] >> 4) * 0x11;
- for (i--; i >= 0; i--) {
- pd[2*i + 1] = (pd[i] & 15) * 0x11;
- pd[2*i + 0] = (pd[i] >> 4) * 0x11;
- }
- }
- pd += s->image_linesize;
- }
- }
+ if (s->bits_per_pixel <= 4)
+ handle_small_bpp(s, p);
/* handle p-frames only if a predecessor frame is available */
if (s->last_picture.f->data[0]) {
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