mirror of https://git.ffmpeg.org/ffmpeg.git
added automatic GIF/animated GIF probing - added GIF as an image format too - added interlaced gif support
Originally committed as revision 1539 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Fabrice Bellard
parent
b2609d4cbd
commit
fcfa89e81c
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@ -18,6 +18,8 @@
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*/
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#include "avformat.h"
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int gif_write(ByteIOContext *pb, AVImageInfo *info);
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//#define DEBUG
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#define MAXBITS 12
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@ -35,8 +37,8 @@ typedef struct GifState {
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int background_color_index;
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int transparent_color_index;
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int color_resolution;
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int image_count;
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uint8_t *image_buf;
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int image_linesize;
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/* after the frame is displayed, the disposal method is used */
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int gce_disposal;
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/* delay during which the frame is shown */
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@ -81,16 +83,60 @@ static const uint16_t mask[17] =
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0x0FFF, 0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF
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};
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static int gif_probe(AVProbeData * pd)
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/* Probe gif video format or gif image format. The current heuristic
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supposes the gif87a is always a single image. For gif89a, we
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consider it as a video only if a GCE extension is present in the
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first kilobyte. */
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static int gif_video_probe(AVProbeData * pd)
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{
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const uint8_t *p, *p_end;
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int bits_per_pixel, has_global_palette, ext_code, ext_len;
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if (pd->buf_size < 24 ||
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memcmp(pd->buf, gif89a_sig, 6) != 0)
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return 0;
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p_end = pd->buf + pd->buf_size;
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p = pd->buf + 6;
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bits_per_pixel = (p[4] & 0x07) + 1;
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has_global_palette = (p[4] & 0x80);
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p += 7;
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if (has_global_palette)
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p += (1 << bits_per_pixel) * 3;
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for(;;) {
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if (p >= p_end)
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return 0;
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if (*p != '!')
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break;
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p++;
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if (p >= p_end)
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return 0;
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ext_code = *p++;
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/* if GCE extension found: it is likely to be an animation */
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if (ext_code == 0xf9)
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return AVPROBE_SCORE_MAX;
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for(;;) {
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if (p >= p_end)
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return 0;
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ext_len = *p++;
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if (ext_len == 0)
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break;
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p += ext_len;
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}
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}
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return 0;
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}
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static int gif_image_probe(AVProbeData * pd)
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{
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if (pd->buf_size >= 24 &&
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(memcmp(pd->buf, gif87a_sig, 6) == 0 ||
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memcmp(pd->buf, gif89a_sig, 6) == 0))
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return AVPROBE_SCORE_MAX;
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return AVPROBE_SCORE_MAX - 1;
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else
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return 0;
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}
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static void GLZWDecodeInit(GifState * s, int csize)
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{
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/* read buffer */
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@ -224,13 +270,12 @@ static int GLZWDecode(GifState * s, uint8_t * buf, int len)
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return len - l;
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}
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static int gif_read_image(AVFormatContext * s1, AVPacket * pkt)
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static int gif_read_image(GifState *s)
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{
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GifState *s = s1->priv_data;
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ByteIOContext *f = s->f;
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int left, top, width, height, bits_per_pixel, code_size, flags;
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int is_interleaved, has_local_palette, y, x, linesize;
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ByteIOContext *f = &s1->pb;
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uint8_t *ptr, *line, *d, *spal, *palette, *sptr;
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int is_interleaved, has_local_palette, y, x, pass, y1, linesize;
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uint8_t *ptr, *line, *d, *spal, *palette, *sptr, *ptr1;
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left = get_le16(f);
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top = get_le16(f);
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@ -251,23 +296,10 @@ static int gif_read_image(AVFormatContext * s1, AVPacket * pkt)
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palette = s->global_palette;
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}
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/* allocate local image (XXX: horrible, needs API change) */
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if (s->image_count == 0) {
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/* modify screen width/height if invalid */
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if (left + width > s->screen_width)
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s->screen_width = left + width;
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if (top + height > s->screen_height)
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s->screen_width = top + height;
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s->image_buf = av_malloc(s->screen_width * s->screen_height * 3);
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if (!s->image_buf)
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return -ENOMEM;
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} else {
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/* verify that all the image is inside the screen dimensions */
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if (left + width > s->screen_width ||
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top + height > s->screen_height)
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return -EINVAL;
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}
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s->image_count++;
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/* verify that all the image is inside the screen dimensions */
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if (left + width > s->screen_width ||
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top + height > s->screen_height)
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return -EINVAL;
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line = av_malloc(width);
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if (!line)
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@ -279,8 +311,11 @@ static int gif_read_image(AVFormatContext * s1, AVPacket * pkt)
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GLZWDecodeInit(s, code_size);
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/* read all the image and transcode it to RGB24 (horrible) */
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linesize = s->screen_width * 3;
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ptr = s->image_buf + top * linesize + (left * 3);
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linesize = s->image_linesize;
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ptr1 = s->image_buf + top * linesize + (left * 3);
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ptr = ptr1;
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pass = 0;
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y1 = 0;
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for (y = 0; y < height; y++) {
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GLZWDecode(s, line, width);
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d = ptr;
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@ -293,29 +328,51 @@ static int gif_read_image(AVFormatContext * s1, AVPacket * pkt)
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d += 3;
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sptr++;
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}
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ptr += linesize;
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if (is_interleaved) {
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switch(pass) {
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default:
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case 0:
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case 1:
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y1 += 8;
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ptr += linesize * 8;
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if (y1 >= height) {
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y1 = 4;
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if (pass == 0)
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ptr = ptr1 + linesize * 4;
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else
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ptr = ptr1 + linesize * 2;
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pass++;
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}
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break;
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case 2:
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y1 += 4;
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ptr += linesize * 4;
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if (y1 >= height) {
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y1 = 1;
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ptr = ptr1 + linesize;
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pass++;
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}
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break;
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case 3:
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y1 += 2;
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ptr += linesize * 2;
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break;
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}
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} else {
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ptr += linesize;
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}
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}
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av_free(line);
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/* read the garbage data until end marker is found */
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while (!s->eob_reached)
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GetCode(s);
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/* output image */
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/* XXX: avoid copying */
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if (av_new_packet(pkt, s->screen_width * s->screen_height * 3)) {
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av_free(line);
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return -EIO;
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}
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pkt->stream_index = 0;
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memcpy(pkt->data, s->image_buf, s->screen_width * s->screen_height * 3);
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return 0;
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}
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static int gif_read_extension(AVFormatContext * s1)
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static int gif_read_extension(GifState *s)
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{
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GifState *s = s1->priv_data;
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ByteIOContext *f = &s1->pb;
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ByteIOContext *f = s->f;
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int ext_code, ext_len, i, gce_flags, gce_transparent_index;
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/* extension */
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@ -359,12 +416,9 @@ static int gif_read_extension(AVFormatContext * s1)
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return 0;
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}
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static int gif_read_header(AVFormatContext * s1,
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AVFormatParameters * ap)
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static int gif_read_header1(GifState *s)
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{
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GifState *s = s1->priv_data;
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ByteIOContext *f = &s1->pb;
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AVStream *st;
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ByteIOContext *f = s->f;
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uint8_t sig[6];
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int ret, v, n;
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int has_global_palette;
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@ -396,6 +450,60 @@ static int gif_read_header(AVFormatContext * s1,
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n = 1 << s->bits_per_pixel;
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get_buffer(f, s->global_palette, n * 3);
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}
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return 0;
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}
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static int gif_parse_next_image(GifState *s)
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{
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ByteIOContext *f = s->f;
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int ret, code;
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for (;;) {
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code = url_fgetc(f);
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#ifdef DEBUG
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printf("gif: code=%02x '%c'\n", code, code);
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#endif
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switch (code) {
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case ',':
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if (gif_read_image(s) < 0)
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return -EIO;
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ret = 0;
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goto the_end;
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case ';':
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/* end of image */
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ret = -EIO;
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goto the_end;
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case '!':
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if (gif_read_extension(s) < 0)
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return -EIO;
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break;
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case EOF:
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default:
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/* error or errneous EOF */
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ret = -EIO;
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goto the_end;
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}
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}
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the_end:
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return ret;
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}
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static int gif_read_header(AVFormatContext * s1,
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AVFormatParameters * ap)
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{
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GifState *s = s1->priv_data;
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ByteIOContext *f = &s1->pb;
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AVStream *st;
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s->f = f;
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if (gif_read_header1(s) < 0)
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return -1;
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/* allocate image buffer */
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s->image_linesize = s->screen_width * 3;
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s->image_buf = av_malloc(s->screen_height * s->image_linesize);
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if (!s->image_buf)
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return -ENOMEM;
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/* now we are ready: build format streams */
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st = av_new_stream(s1, 0);
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if (!st)
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@ -414,37 +522,20 @@ static int gif_read_header(AVFormatContext * s1,
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static int gif_read_packet(AVFormatContext * s1,
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AVPacket * pkt)
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{
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ByteIOContext *f = &s1->pb;
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int ret, code;
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GifState *s = s1->priv_data;
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int ret;
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for (;;) {
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code = url_fgetc(f);
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#ifdef DEBUG
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printf("gif: code=%02x '%c'\n", code, code);
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#endif
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switch (code) {
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case ',':
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if (gif_read_image(s1, pkt) < 0)
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return -EIO;
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ret = 0;
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goto the_end;
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case ';':
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/* end of image */
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ret = -EIO;
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goto the_end;
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case '!':
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if (gif_read_extension(s1) < 0)
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return -EIO;
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break;
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case EOF:
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default:
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/* error or errneous EOF */
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ret = -EIO;
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goto the_end;
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}
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ret = gif_parse_next_image(s);
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if (ret < 0)
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return ret;
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/* XXX: avoid copying */
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if (av_new_packet(pkt, s->screen_width * s->screen_height * 3)) {
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return -EIO;
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}
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the_end:
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return ret;
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pkt->stream_index = 0;
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memcpy(pkt->data, s->image_buf, s->screen_width * s->screen_height * 3);
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return 0;
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}
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static int gif_read_close(AVFormatContext *s1)
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@ -454,13 +545,48 @@ static int gif_read_close(AVFormatContext *s1)
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return 0;
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}
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/* read gif as image */
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static int gif_read(ByteIOContext *f,
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int (*alloc_cb)(void *opaque, AVImageInfo *info), void *opaque)
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{
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GifState s1, *s = &s1;
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AVImageInfo info1, *info = &info1;
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int ret;
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memset(s, 0, sizeof(GifState));
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s->f = f;
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if (gif_read_header1(s) < 0)
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return -1;
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info->width = s->screen_width;
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info->height = s->screen_height;
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info->pix_fmt = PIX_FMT_RGB24;
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ret = alloc_cb(opaque, info);
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if (ret)
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return ret;
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s->image_buf = info->pict.data[0];
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s->image_linesize = info->pict.linesize[0];
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if (gif_parse_next_image(s) < 0)
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return -1;
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return 0;
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}
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AVInputFormat gif_iformat =
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{
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"gif",
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"gif format",
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sizeof(GifState),
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gif_probe,
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gif_video_probe,
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gif_read_header,
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gif_read_packet,
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gif_read_close,
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};
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AVImageFormat gif_image_format = {
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"gif",
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"gif",
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gif_image_probe,
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gif_read,
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(1 << PIX_FMT_RGB24),
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gif_write,
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};
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