#include "libavutil/imgutils.h"
#include "libavutil/log.h"
#include "libavutil/opt.h"
-
-/* XXX: random value that shouldn't be taken into effect if there is no
- * transparent color in the palette (the transparency bit will be set to 0) */
-#define DEFAULT_TRANSPARENCY_INDEX 0x1f
-
-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_image_write_header(AVIOContext *pb, AVStream *st,
- int loop_count, uint32_t *palette)
-{
- int i;
- int64_t aspect = 0;
- const AVRational sar = st->sample_aspect_ratio;
-
- if (sar.num > 0 && sar.den > 0) {
- aspect = sar.num * 64LL / sar.den - 15;
- if (aspect < 0 || aspect > 255)
- aspect = 0;
- }
-
- avio_write(pb, "GIF", 3);
- avio_write(pb, "89a", 3);
- avio_wl16(pb, st->codecpar->width);
- avio_wl16(pb, st->codecpar->height);
-
- if (palette) {
- const int bcid = get_palette_transparency_index(palette);
-
- avio_w8(pb, 0xf7); /* flags: global clut, 256 entries */
- avio_w8(pb, bcid < 0 ? DEFAULT_TRANSPARENCY_INDEX : bcid); /* background color index */
- avio_w8(pb, aspect);
- for (i = 0; i < 256; i++) {
- const uint32_t v = palette[i] & 0xffffff;
- avio_wb24(pb, v);
- }
- } else {
- avio_w8(pb, 0); /* flags */
- avio_w8(pb, 0); /* background color index */
- avio_w8(pb, aspect);
- }
-
-
- if (loop_count >= 0 ) {
- /* "NETSCAPE EXTENSION" for looped animation GIF */
- avio_w8(pb, 0x21); /* GIF Extension code */
- avio_w8(pb, 0xff); /* Application Extension Label */
- avio_w8(pb, 0x0b); /* Length of Application Block */
- avio_write(pb, "NETSCAPE2.0", sizeof("NETSCAPE2.0") - 1);
- avio_w8(pb, 0x03); /* Length of Data Sub-Block */
- avio_w8(pb, 0x01);
- avio_wl16(pb, (uint16_t)loop_count);
- avio_w8(pb, 0x00); /* Data Sub-block Terminator */
- }
-
- avio_flush(pb);
- return 0;
-}
+#include "libavcodec/bytestream.h"
+#include "libavcodec/gif.h"
typedef struct GIFContext {
AVClass *class;
int loop;
int last_delay;
- AVPacket *prev_pkt;
int duration;
+ int64_t last_pos;
+ int have_end;
+ AVPacket *prev_pkt;
} GIFContext;
static int gif_write_header(AVFormatContext *s)
{
- GIFContext *gif = s->priv_data;
- AVCodecParameters *video_par;
- uint32_t palette[AVPALETTE_COUNT];
-
if (s->nb_streams != 1 ||
s->streams[0]->codecpar->codec_type != AVMEDIA_TYPE_VIDEO ||
s->streams[0]->codecpar->codec_id != AV_CODEC_ID_GIF) {
return AVERROR(EINVAL);
}
- video_par = s->streams[0]->codecpar;
-
avpriv_set_pts_info(s->streams[0], 64, 1, 100);
- if (avpriv_set_systematic_pal2(palette, video_par->format) < 0) {
- av_assert0(video_par->format == AV_PIX_FMT_PAL8);
- /* delay header writing: we wait for the first palette to put it
- * globally */
- } else {
- gif_image_write_header(s->pb, s->streams[0], gif->loop, palette);
- }
return 0;
}
-static int flush_packet(AVFormatContext *s, AVPacket *new)
+static int gif_parse_packet(AVFormatContext *s, uint8_t *data, int size)
{
- GIFContext *gif = s->priv_data;
- int size, bcid;
- AVIOContext *pb = s->pb;
- const uint32_t *palette;
- AVPacket *pkt = gif->prev_pkt;
-
- if (!pkt)
- return 0;
+ GetByteContext gb;
+ int x;
+
+ bytestream2_init(&gb, data, size);
+
+ while (bytestream2_get_bytes_left(&gb) > 0) {
+ x = bytestream2_get_byte(&gb);
+ if (x != GIF_EXTENSION_INTRODUCER)
+ return 0;
+
+ x = bytestream2_get_byte(&gb);
+ while (x != GIF_GCE_EXT_LABEL && bytestream2_get_bytes_left(&gb) > 0) {
+ int block_size = bytestream2_get_byte(&gb);
+ if (!block_size)
+ break;
+ bytestream2_skip(&gb, block_size);
+ }
- /* Mark one colour as transparent if the input palette contains at least
- * one colour that is more than 50% transparent. */
- palette = (uint32_t*)av_packet_get_side_data(pkt, AV_PKT_DATA_PALETTE, &size);
- if (palette && size != AVPALETTE_SIZE) {
- av_log(s, AV_LOG_ERROR, "Invalid palette extradata\n");
- return AVERROR_INVALIDDATA;
+ if (x == GIF_GCE_EXT_LABEL)
+ return bytestream2_tell(&gb) + 2;
}
- bcid = get_palette_transparency_index(palette);
+ return 0;
+}
+
+static int gif_get_delay(GIFContext *gif, AVPacket *prev, AVPacket *new)
+{
if (new && new->pts != AV_NOPTS_VALUE)
- gif->duration = av_clip_uint16(new->pts - gif->prev_pkt->pts);
+ gif->duration = av_clip_uint16(new->pts - prev->pts);
else if (!new && gif->last_delay >= 0)
gif->duration = gif->last_delay;
- /* graphic control extension block */
- avio_w8(pb, 0x21);
- avio_w8(pb, 0xf9);
- avio_w8(pb, 0x04); /* block size */
- avio_w8(pb, 1<<2 | (bcid >= 0));
- avio_wl16(pb, gif->duration);
- avio_w8(pb, bcid < 0 ? DEFAULT_TRANSPARENCY_INDEX : bcid);
- avio_w8(pb, 0x00);
-
- avio_write(pb, pkt->data, pkt->size);
-
- av_packet_unref(gif->prev_pkt);
- if (new)
- av_packet_ref(gif->prev_pkt, new);
-
- return 0;
+ return gif->duration;
}
-static int gif_write_packet(AVFormatContext *s, AVPacket *pkt)
+static int gif_write_packet(AVFormatContext *s, AVPacket *new_pkt)
{
GIFContext *gif = s->priv_data;
- AVStream *video_st = s->streams[0];
+ AVIOContext *pb = s->pb;
+ AVPacket *pkt = gif->prev_pkt;
if (!gif->prev_pkt) {
gif->prev_pkt = av_packet_alloc();
if (!gif->prev_pkt)
return AVERROR(ENOMEM);
+ return av_packet_ref(gif->prev_pkt, new_pkt);
+ }
+
+ gif->last_pos = avio_tell(pb);
+ if (pkt->size > 0)
+ gif->have_end = pkt->data[pkt->size - 1] == GIF_TRAILER;
+
+ if (!gif->last_pos) {
+ int delay_pos;
+ int off = 13;
+
+ if (pkt->size < 13)
+ return AVERROR(EINVAL);
- /* Write the first palette as global palette */
- if (video_st->codecpar->format == AV_PIX_FMT_PAL8) {
- int size;
- void *palette = av_packet_get_side_data(pkt, AV_PKT_DATA_PALETTE, &size);
-
- if (!palette) {
- av_log(s, AV_LOG_ERROR, "PAL8 packet is missing palette in extradata\n");
- return AVERROR_INVALIDDATA;
- }
- if (size != AVPALETTE_SIZE) {
- av_log(s, AV_LOG_ERROR, "Invalid palette extradata\n");
- return AVERROR_INVALIDDATA;
- }
- gif_image_write_header(s->pb, video_st, gif->loop, palette);
+ if (pkt->data[10] & 0x80)
+ off += 3 * (1 << ((pkt->data[10] & 0x07) + 1));
+
+ if (pkt->size < off + 2)
+ return AVERROR(EINVAL);
+
+ avio_write(pb, pkt->data, off);
+
+ if (pkt->data[off] == GIF_EXTENSION_INTRODUCER && pkt->data[off + 1] == 0xff)
+ off += 19;
+
+ if (pkt->size <= off)
+ return AVERROR(EINVAL);
+
+ /* "NETSCAPE EXTENSION" for looped animation GIF */
+ if (gif->loop >= 0) {
+ avio_w8(pb, GIF_EXTENSION_INTRODUCER); /* GIF Extension code */
+ avio_w8(pb, GIF_APP_EXT_LABEL); /* Application Extension Label */
+ avio_w8(pb, 0x0b); /* Length of Application Block */
+ avio_write(pb, "NETSCAPE2.0", sizeof("NETSCAPE2.0") - 1);
+ avio_w8(pb, 0x03); /* Length of Data Sub-Block */
+ avio_w8(pb, 0x01);
+ avio_wl16(pb, (uint16_t)gif->loop);
+ avio_w8(pb, 0x00); /* Data Sub-block Terminator */
}
- return av_packet_ref(gif->prev_pkt, pkt);
+ delay_pos = gif_parse_packet(s, pkt->data + off, pkt->size - off);
+ if (delay_pos > 0 && delay_pos < pkt->size - off - 2) {
+ avio_write(pb, pkt->data + off, delay_pos);
+ avio_wl16(pb, gif_get_delay(gif, pkt, new_pkt));
+ avio_write(pb, pkt->data + off + delay_pos + 2, pkt->size - off - delay_pos - 2);
+ } else {
+ avio_write(pb, pkt->data + off, pkt->size - off);
+ }
+ } else {
+ int delay_pos = gif_parse_packet(s, pkt->data, pkt->size);
+
+ if (delay_pos > 0 && delay_pos < pkt->size - 2) {
+ avio_write(pb, pkt->data, delay_pos);
+ avio_wl16(pb, gif_get_delay(gif, pkt, new_pkt));
+ avio_write(pb, pkt->data + delay_pos + 2, pkt->size - delay_pos - 2);
+ } else {
+ avio_write(pb, pkt->data, pkt->size);
+ }
}
- return flush_packet(s, pkt);
+
+ av_packet_unref(gif->prev_pkt);
+ if (new_pkt)
+ return av_packet_ref(gif->prev_pkt, new_pkt);
+
+ return 0;
}
static int gif_write_trailer(AVFormatContext *s)
GIFContext *gif = s->priv_data;
AVIOContext *pb = s->pb;
- flush_packet(s, NULL);
- av_freep(&gif->prev_pkt);
- avio_w8(pb, 0x3b);
+ if (!gif->prev_pkt)
+ return AVERROR(EINVAL);
+
+ gif_write_packet(s, NULL);
+
+ if (!gif->have_end)
+ avio_w8(pb, GIF_TRAILER);
+ av_packet_free(&gif->prev_pkt);
return 0;
}
.option = options,
};
-AVOutputFormat ff_gif_muxer = {
+const AVOutputFormat ff_gif_muxer = {
.name = "gif",
- .long_name = NULL_IF_CONFIG_SMALL("GIF Animation"),
+ .long_name = NULL_IF_CONFIG_SMALL("CompuServe Graphics Interchange Format (GIF)"),
.mime_type = "image/gif",
.extensions = "gif",
.priv_data_size = sizeof(GIFContext),
projects / ffmpeg / blobdiff