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Code Issues Releases Activity

lavc/pngdec: remove unnecessary context variables

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Do not store the image buffer pointer/linesize in the context, just
access them directly from the frame.
Stop assuming that linesize is the same for the current and last frame.
This commit is contained in:
Anton Khirnov 2021-04-02 10:45:27 +02:00
parent 5a50bd88db
commit 89ea5057bf
1 changed files with 17 additions and 19 deletions
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36
libavcodec/pngdec.c
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@ -77,8 +77,6 @@ typedef struct PNGDecContext {
int has_trns;
uint8_t transparent_color_be[6];
uint8_t *image_buf;
int image_linesize;
uint32_t palette[256];
uint8_t *crow_buf;
uint8_t *last_row;
@ -330,27 +328,27 @@ static int percent_missing(PNGDecContext *s)
}
/* process exactly one decompressed row */
static void png_handle_row(PNGDecContext *s)
static void png_handle_row(PNGDecContext *s, uint8_t *dst, ptrdiff_t dst_stride)
{
uint8_t *ptr, *last_row;
int got_line;
if (!s->interlace_type) {
ptr = s->image_buf + s->image_linesize * (s->y + s->y_offset) + s->x_offset * s->bpp;
ptr = dst + dst_stride * (s->y + s->y_offset) + s->x_offset * s->bpp;
if (s->y == 0)
last_row = s->last_row;
else
last_row = ptr - s->image_linesize;
last_row = ptr - dst_stride;
ff_png_filter_row(&s->dsp, ptr, s->crow_buf[0], s->crow_buf + 1,
last_row, s->row_size, s->bpp);
/* loco lags by 1 row so that it doesn't interfere with top prediction */
if (s->filter_type == PNG_FILTER_TYPE_LOCO && s->y > 0) {
if (s->bit_depth == 16) {
deloco_rgb16((uint16_t *)(ptr - s->image_linesize), s->row_size / 2,
deloco_rgb16((uint16_t *)(ptr - dst_stride), s->row_size / 2,
s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
} else {
deloco_rgb8(ptr - s->image_linesize, s->row_size,
deloco_rgb8(ptr - dst_stride, s->row_size,
s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
}
}
@ -370,7 +368,7 @@ static void png_handle_row(PNGDecContext *s)
} else {
got_line = 0;
for (;;) {
ptr = s->image_buf + s->image_linesize * (s->y + s->y_offset) + s->x_offset * s->bpp;
ptr = dst + dst_stride * (s->y + s->y_offset) + s->x_offset * s->bpp;
if ((ff_png_pass_ymask[s->pass] << (s->y & 7)) & 0x80) {
/* if we already read one row, it is time to stop to
* wait for the next one */
@ -411,7 +409,8 @@ the_end:;
}
}
static int png_decode_idat(PNGDecContext *s, int length)
static int png_decode_idat(PNGDecContext *s, int length,
uint8_t *dst, ptrdiff_t dst_stride)
{
int ret;
s->zstream.avail_in = FFMIN(length, bytestream2_get_bytes_left(&s->gb));
@ -427,7 +426,7 @@ static int png_decode_idat(PNGDecContext *s, int length)
}
if (s->zstream.avail_out == 0) {
if (!(s->pic_state & PNG_ALLIMAGE)) {
png_handle_row(s);
png_handle_row(s, dst, dst_stride);
}
s->zstream.avail_out = s->crow_size;
s->zstream.next_out = s->crow_buf;
@ -732,8 +731,7 @@ static int decode_idat_chunk(AVCodecContext *avctx, PNGDecContext *s,
}
ff_dlog(avctx, "row_size=%d crow_size =%d\n",
s->row_size, s->crow_size);
s->image_buf = p->data[0];
s->image_linesize = p->linesize[0];
/* copy the palette if needed */
if (avctx->pix_fmt == AV_PIX_FMT_PAL8)
memcpy(p->data[1], s->palette, 256 * sizeof(uint32_t));
@ -764,7 +762,7 @@ static int decode_idat_chunk(AVCodecContext *avctx, PNGDecContext *s,
if (s->has_trns && s->color_type != PNG_COLOR_TYPE_PALETTE)
s->bpp -= byte_depth;
ret = png_decode_idat(s, length);
ret = png_decode_idat(s, length, p->data[0], p->linesize[0]);
if (s->has_trns && s->color_type != PNG_COLOR_TYPE_PALETTE)
s->bpp += byte_depth;
@ -913,7 +911,7 @@ static void handle_small_bpp(PNGDecContext *s, AVFrame *p)
pd[8*i + 1]= (pd[i]>>6) & 1;
pd[8*i + 0]= pd[i]>>7;
}
pd += s->image_linesize;
pd += p->linesize[0];
}
} else if (s->bits_per_pixel == 2) {
int i, j;
@ -941,7 +939,7 @@ static void handle_small_bpp(PNGDecContext *s, AVFrame *p)
pd[4*i + 0]= ( pd[i]>>6 )*0x55;
}
}
pd += s->image_linesize;
pd += p->linesize[0];
}
} else if (s->bits_per_pixel == 4) {
int i, j;
@ -961,7 +959,7 @@ static void handle_small_bpp(PNGDecContext *s, AVFrame *p)
pd[2*i + 0] = (pd[i] >> 4) * 0x11;
}
}
pd += s->image_linesize;
pd += p->linesize[0];
}
}
}
@ -1056,8 +1054,8 @@ static void handle_p_frame_png(PNGDecContext *s, AVFrame *p)
for (j = 0; j < s->height; j++) {
for (i = 0; i < ls; i++)
pd[i] += pd_last[i];
pd += s->image_linesize;
pd_last += s->image_linesize;
pd += p->linesize[0];
pd_last += s->last_picture.f->linesize[0];
}
}
@ -1401,7 +1399,7 @@ exit_loop:
av_assert0(s->bit_depth > 1);
for (y = 0; y < s->height; ++y) {
uint8_t *row = &s->image_buf[s->image_linesize * y];
uint8_t *row = &p->data[0][p->linesize[0] * y];
if (s->bpp == 2 && byte_depth == 1) {
uint8_t *pixel = &row[2 * s->width - 1];