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Diffstat (limited to 'libavcodec/gif.c')
-rw-r--r--libavcodec/gif.c127
1 files changed, 72 insertions, 55 deletions
diff --git a/libavcodec/gif.c b/libavcodec/gif.c
index d9c99d52cf..3074b7f7db 100644
--- a/libavcodec/gif.c
+++ b/libavcodec/gif.c
@@ -39,17 +39,19 @@
#include "put_bits.h"
+#define DEFAULT_TRANSPARENCY_INDEX 0x1f
+
typedef struct GIFContext {
const AVClass *class;
LZWState *lzw;
uint8_t *buf;
int buf_size;
+ int is_first_frame;
AVFrame *last_frame;
int flags;
uint32_t palette[AVPALETTE_COUNT]; ///< local reference palette for !pal8
int palette_loaded;
int transparent_index;
- uint8_t *pal_exdata;
uint8_t *tmpl; ///< temporary line buffer
} GIFContext;
@@ -58,6 +60,24 @@ enum {
GF_TRANSDIFF = 1<<1,
};
+static int get_palette_transparency_index(const uint32_t *palette)
+{
+ int transparent_color_index = -1;
+ unsigned i, smallest_alpha = 0xff;
+
+ if (!palette)
+ return -1;
+
+ for (i = 0; i < AVPALETTE_COUNT; i++) {
+ const uint32_t v = palette[i];
+ if (v >> 24 < smallest_alpha) {
+ smallest_alpha = v >> 24;
+ transparent_color_index = i;
+ }
+ }
+ return smallest_alpha < 128 ? transparent_color_index : -1;
+}
+
static int pick_palette_entry(const uint8_t *buf, int linesize, int w, int h)
{
int histogram[AVPALETTE_COUNT] = {0};
@@ -83,7 +103,7 @@ static int gif_image_write_image(AVCodecContext *avctx,
GIFContext *s = avctx->priv_data;
int len = 0, height = avctx->height, width = avctx->width, x, y;
int x_start = 0, y_start = 0, trans = s->transparent_index;
- int honor_transparency = (s->flags & GF_TRANSDIFF) && s->last_frame && !palette;
+ int bcid = -1, honor_transparency = (s->flags & GF_TRANSDIFF) && s->last_frame && !palette;
const uint8_t *ptr;
/* Crop image */
@@ -137,6 +157,54 @@ static int gif_image_write_image(AVCodecContext *avctx,
width, height, x_start, y_start, avctx->width, avctx->height);
}
+ if (s->is_first_frame) { /* GIF header */
+ const uint32_t *global_palette = palette ? palette : s->palette;
+ const AVRational sar = avctx->sample_aspect_ratio;
+ int64_t aspect = 0;
+
+ if (sar.num > 0 && sar.den > 0) {
+ aspect = sar.num * 64LL / sar.den - 15;
+ if (aspect < 0 || aspect > 255)
+ aspect = 0;
+ }
+
+ bytestream_put_buffer(bytestream, gif89a_sig, sizeof(gif89a_sig));
+ bytestream_put_le16(bytestream, avctx->width);
+ bytestream_put_le16(bytestream, avctx->height);
+
+ bcid = get_palette_transparency_index(global_palette);
+
+ bytestream_put_byte(bytestream, 0xf7); /* flags: global clut, 256 entries */
+ bytestream_put_byte(bytestream, bcid < 0 ? DEFAULT_TRANSPARENCY_INDEX : bcid); /* background color index */
+ bytestream_put_byte(bytestream, aspect);
+ for (int i = 0; i < 256; i++) {
+ const uint32_t v = global_palette[i] & 0xffffff;
+ bytestream_put_be24(bytestream, v);
+ }
+
+ s->is_first_frame = 0;
+ }
+
+ if (honor_transparency && trans < 0) {
+ trans = pick_palette_entry(buf + y_start*linesize + x_start,
+ linesize, width, height);
+ if (trans < 0) // TODO, patch welcome
+ av_log(avctx, AV_LOG_DEBUG, "No available color, can not use transparency\n");
+ }
+ if (trans < 0)
+ honor_transparency = 0;
+
+ bcid = (honor_transparency && trans >= 0) ? trans : get_palette_transparency_index(palette);
+
+ /* graphic control extension */
+ bytestream_put_byte(bytestream, GIF_EXTENSION_INTRODUCER);
+ bytestream_put_byte(bytestream, GIF_GCE_EXT_LABEL);
+ bytestream_put_byte(bytestream, 0x04); /* block size */
+ bytestream_put_byte(bytestream, 1<<2 | (bcid >= 0));
+ bytestream_put_le16(bytestream, 5); // default delay
+ bytestream_put_byte(bytestream, bcid < 0 ? DEFAULT_TRANSPARENCY_INDEX : bcid);
+ bytestream_put_byte(bytestream, 0x00);
+
/* image block */
bytestream_put_byte(bytestream, GIF_IMAGE_SEPARATOR);
bytestream_put_le16(bytestream, x_start);
@@ -155,24 +223,6 @@ static int gif_image_write_image(AVCodecContext *avctx,
}
}
- if (honor_transparency && trans < 0) {
- trans = pick_palette_entry(buf + y_start*linesize + x_start,
- linesize, width, height);
- if (trans < 0) { // TODO, patch welcome
- av_log(avctx, AV_LOG_DEBUG, "No available color, can not use transparency\n");
- } else {
- uint8_t *pal_exdata = s->pal_exdata;
- if (!pal_exdata)
- pal_exdata = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE, AVPALETTE_SIZE);
- if (!pal_exdata)
- return AVERROR(ENOMEM);
- memcpy(pal_exdata, s->palette, AVPALETTE_SIZE);
- pal_exdata[trans*4 + 3*!HAVE_BIGENDIAN] = 0x00;
- }
- }
- if (trans < 0)
- honor_transparency = 0;
-
bytestream_put_byte(bytestream, 0x08);
ff_lzw_encode_init(s->lzw, s->buf, s->buf_size,
@@ -222,14 +272,9 @@ static av_cold int gif_encode_init(AVCodecContext *avctx)
av_log(avctx, AV_LOG_ERROR, "GIF does not support resolutions above 65535x65535\n");
return AVERROR(EINVAL);
}
-#if FF_API_CODED_FRAME
-FF_DISABLE_DEPRECATION_WARNINGS
- avctx->coded_frame->pict_type = AV_PICTURE_TYPE_I;
- avctx->coded_frame->key_frame = 1;
-FF_ENABLE_DEPRECATION_WARNINGS
-#endif
s->transparent_index = -1;
+ s->is_first_frame = 1;
s->lzw = av_mallocz(ff_lzw_encode_state_size);
s->buf_size = avctx->width*avctx->height*2 + 1000;
@@ -244,25 +289,6 @@ FF_ENABLE_DEPRECATION_WARNINGS
return 0;
}
-/* FIXME: duplicated with lavc */
-static int get_palette_transparency_index(const uint32_t *palette)
-{
- int transparent_color_index = -1;
- unsigned i, smallest_alpha = 0xff;
-
- if (!palette)
- return -1;
-
- for (i = 0; i < AVPALETTE_COUNT; i++) {
- const uint32_t v = palette[i];
- if (v >> 24 < smallest_alpha) {
- smallest_alpha = v >> 24;
- transparent_color_index = i;
- }
- }
- return smallest_alpha < 128 ? transparent_color_index : -1;
-}
-
static int gif_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
const AVFrame *pict, int *got_packet)
{
@@ -277,22 +303,12 @@ static int gif_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
end = pkt->data + pkt->size;
if (avctx->pix_fmt == AV_PIX_FMT_PAL8) {
- uint8_t *pal_exdata = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE, AVPALETTE_SIZE);
- if (!pal_exdata)
- return AVERROR(ENOMEM);
- memcpy(pal_exdata, pict->data[1], AVPALETTE_SIZE);
palette = (uint32_t*)pict->data[1];
- s->pal_exdata = pal_exdata;
-
- /* The first palette with PAL8 will be used as generic palette by the
- * muxer so we don't need to write it locally in the packet. We store
- * it as a reference here in case it changes later. */
if (!s->palette_loaded) {
memcpy(s->palette, palette, AVPALETTE_SIZE);
s->transparent_index = get_palette_transparency_index(palette);
s->palette_loaded = 1;
- palette = NULL;
} else if (!memcmp(s->palette, palette, AVPALETTE_SIZE)) {
palette = NULL;
}
@@ -305,6 +321,7 @@ static int gif_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
if (!s->last_frame)
return AVERROR(ENOMEM);
}
+
av_frame_unref(s->last_frame);
ret = av_frame_ref(s->last_frame, (AVFrame*)pict);
if (ret < 0)
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-07 10:24:03 +0000