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-rw-r--r--libavcodec/gif.c84
1 files changed, 40 insertions, 44 deletions
diff --git a/libavcodec/gif.c b/libavcodec/gif.c
index 98ab767c40..cd7b76155f 100644
--- a/libavcodec/gif.c
+++ b/libavcodec/gif.c
@@ -51,61 +51,54 @@ typedef struct {
uint8_t *buf;
} GIFContext;
-/* GIF header */
-static int gif_image_write_header(AVCodecContext *avctx,
- uint8_t **bytestream, uint32_t *palette)
-{
- int i;
- unsigned int v, smallest_alpha = 0xFF, alpha_component = 0;
-
- bytestream_put_buffer(bytestream, "GIF", 3);
- bytestream_put_buffer(bytestream, "89a", 3);
- bytestream_put_le16(bytestream, avctx->width);
- bytestream_put_le16(bytestream, avctx->height);
-
- bytestream_put_byte(bytestream, 0xf7); /* flags: global clut, 256 entries */
- bytestream_put_byte(bytestream, 0x1f); /* background color index */
- bytestream_put_byte(bytestream, 0); /* aspect ratio */
-
- /* the global palette */
- for(i=0;i<256;i++) {
- v = palette[i];
- bytestream_put_be24(bytestream, v);
- if (v >> 24 < smallest_alpha) {
- smallest_alpha = v >> 24;
- alpha_component = i;
- }
- }
-
- if (smallest_alpha < 128) {
- bytestream_put_byte(bytestream, 0x21); /* Extension Introducer */
- bytestream_put_byte(bytestream, 0xf9); /* Graphic Control Label */
- bytestream_put_byte(bytestream, 0x04); /* block length */
- bytestream_put_byte(bytestream, 0x01); /* Transparent Color Flag */
- bytestream_put_le16(bytestream, 0x00); /* no delay */
- bytestream_put_byte(bytestream, alpha_component);
- bytestream_put_byte(bytestream, 0x00);
- }
-
- return 0;
-}
-
static int gif_image_write_image(AVCodecContext *avctx,
uint8_t **bytestream, uint8_t *end,
+ const uint32_t *palette,
const uint8_t *buf, int linesize)
{
GIFContext *s = avctx->priv_data;
int len = 0, height;
const uint8_t *ptr;
- /* image block */
+ /* Mark one colour as transparent if the input palette contains at least
+ * one colour that is more than 50% transparent. */
+ if (palette) {
+ unsigned i, smallest_alpha = 0xFF, alpha_component = 0;
+ for (i = 0; i < AVPALETTE_COUNT; i++) {
+ const uint32_t v = palette[i];
+ if (v >> 24 < smallest_alpha) {
+ smallest_alpha = v >> 24;
+ alpha_component = i;
+ }
+ }
+ if (smallest_alpha < 128) {
+ bytestream_put_byte(bytestream, 0x21); /* Extension Introducer */
+ bytestream_put_byte(bytestream, 0xf9); /* Graphic Control Label */
+ bytestream_put_byte(bytestream, 0x04); /* block length */
+ bytestream_put_byte(bytestream, 0x01); /* Transparent Color Flag */
+ bytestream_put_le16(bytestream, 0x00); /* no delay */
+ bytestream_put_byte(bytestream, alpha_component);
+ bytestream_put_byte(bytestream, 0x00);
+ }
+ }
+
+ /* image block */
bytestream_put_byte(bytestream, 0x2c);
bytestream_put_le16(bytestream, 0);
bytestream_put_le16(bytestream, 0);
bytestream_put_le16(bytestream, avctx->width);
bytestream_put_le16(bytestream, avctx->height);
+
+ if (!palette) {
bytestream_put_byte(bytestream, 0x00); /* flags */
- /* no local clut */
+ } else {
+ unsigned i;
+ bytestream_put_byte(bytestream, 1<<7 | 0x7); /* flags */
+ for (i = 0; i < AVPALETTE_COUNT; i++) {
+ const uint32_t v = palette[i];
+ bytestream_put_be24(bytestream, v);
+ }
+ }
bytestream_put_byte(bytestream, 0x08);
@@ -130,7 +123,6 @@ static int gif_image_write_image(AVCodecContext *avctx,
len -= size;
}
bytestream_put_byte(bytestream, 0x00); /* end of image block */
- bytestream_put_byte(bytestream, 0x3b);
return 0;
}
@@ -160,6 +152,7 @@ static int gif_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
GIFContext *s = avctx->priv_data;
AVFrame *const p = &s->picture;
uint8_t *outbuf_ptr, *end;
+ const uint32_t *palette = NULL;
int ret;
if ((ret = ff_alloc_packet2(avctx, pkt, avctx->width*avctx->height*7/5 + FF_MIN_BUFFER_SIZE)) < 0)
@@ -170,8 +163,11 @@ static int gif_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
*p = *pict;
p->pict_type = AV_PICTURE_TYPE_I;
p->key_frame = 1;
- gif_image_write_header(avctx, &outbuf_ptr, (uint32_t *)pict->data[1]);
- gif_image_write_image(avctx, &outbuf_ptr, end, pict->data[0], pict->linesize[0]);
+
+ if (avctx->pix_fmt == AV_PIX_FMT_PAL8)
+ palette = (uint32_t*)p->data[1];
+
+ gif_image_write_image(avctx, &outbuf_ptr, end, palette, pict->data[0], pict->linesize[0]);
pkt->size = outbuf_ptr - pkt->data;
pkt->flags |= AV_PKT_FLAG_KEY;