subtitle codec type support

Originally committed as revision 4346 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 459 insertions, 0 deletions

diff --git a/libavcodec/dvdsub.c b/libavcodec/dvdsub.c
new file mode 100644
index 0000000000..af5d9aca02
--- /dev/null
+++ b/libavcodec/dvdsub.c
@@ -0,0 +1,459 @@
+/*
+ * DVD subtitle decoding for ffmpeg
+ * Copyright (c) 2005 Fabrice Bellard.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+#include "avcodec.h"
+
+//#define DEBUG
+
+typedef struct DVDSubContext {
+} DVDSubContext;
+
+static int dvdsub_init_decoder(AVCodecContext *avctx)
+{
+    return 0;
+}
+
+uint16_t getbe16(const uint8_t *p)
+{
+    return (p[0] << 8) | p[1];
+}
+
+int get_nibble(const uint8_t *buf, int nibble_offset)
+{
+    return (buf[nibble_offset >> 1] >> ((1 - (nibble_offset & 1)) << 2)) & 0xf;
+}
+
+static int decode_rle(uint8_t *bitmap, int linesize, int w, int h, 
+                      const uint8_t *buf, int nibble_offset, int buf_size)
+{
+    unsigned int v;
+    int x, y, len, color, nibble_end;
+    uint8_t *d;
+
+    nibble_end = buf_size * 2;
+    x = 0;
+    y = 0;
+    d = bitmap;
+    for(;;) {
+        if (nibble_offset >= nibble_end)
+            return -1;
+        v = get_nibble(buf, nibble_offset++);
+        if (v < 0x4) {
+            v = (v << 4) | get_nibble(buf, nibble_offset++);
+            if (v < 0x10) {
+                v = (v << 4) | get_nibble(buf, nibble_offset++);
+                if (v < 0x040) {
+                    v = (v << 4) | get_nibble(buf, nibble_offset++);
+                    if (v < 4) {
+                        v |= (w - x) << 2;
+                    }
+                }
+            }
+        }
+        len = v >> 2;
+        if (len > (w - x))
+            len = (w - x);
+        color = v & 0x03;
+        memset(d + x, color, len);
+        x += len;
+        if (x >= w) {
+            y++;
+            if (y >= h)
+                break;
+            d += linesize;
+            x = 0;
+            /* byte align */
+            nibble_offset += (nibble_offset & 1);
+        }
+    }
+    return 0;
+}
+
+static void guess_palette(uint32_t *rgba_palette,
+                          uint8_t *palette,
+                          uint8_t *alpha,
+                          uint32_t subtitle_color)
+{
+    uint8_t color_used[16];
+    int nb_opaque_colors, i, level, j, r, g, b;
+    
+    for(i = 0; i < 4; i++)
+        rgba_palette[i] = 0;
+
+    memset(color_used, 0, 16);
+    nb_opaque_colors = 0;
+    for(i = 0; i < 4; i++) {
+        if (alpha[i] != 0 && !color_used[palette[i]]) {
+            color_used[palette[i]] = 1;
+            nb_opaque_colors++;
+        }
+    }
+    
+    if (nb_opaque_colors == 0)
+        return;
+    
+    j = 0;
+    memset(color_used, 0, 16);
+    for(i = 0; i < 4; i++) {
+        if (alpha[i] != 0) {
+            if (!color_used[palette[i]])  {
+                level = (0xff * (j + 1)) / nb_opaque_colors;
+                r = (((subtitle_color >> 16) & 0xff) * level) >> 8;
+                g = (((subtitle_color >> 8) & 0xff) * level) >> 8;
+                b = (((subtitle_color >> 0) & 0xff) * level) >> 8;
+                rgba_palette[i] = b | (g << 8) | (r << 16) | (0xff << 24);
+                color_used[palette[i]] = (i + 1);
+                j++;
+            } else {
+                rgba_palette[i] = rgba_palette[color_used[palette[i]] - 1];
+            }
+        }
+    }
+}
+
+static int decode_dvd_subtitles(AVSubtitle *sub_header, 
+                                const uint8_t *buf, int buf_size)
+{
+    int cmd_pos, pos, cmd, x1, y1, x2, y2, offset1, offset2, next_cmd_pos;
+    uint8_t palette[4], alpha[4];
+    int date;
+    
+    if (buf_size < 4)
+        return -1;
+    sub_header->bitmap = NULL;
+    sub_header->rgba_palette = NULL;
+    sub_header->start_display_time = 0;
+    sub_header->end_display_time = 0;
+
+    cmd_pos = getbe16(buf + 2);
+    while ((cmd_pos + 4) < buf_size) {
+        date = getbe16(buf + cmd_pos);
+        next_cmd_pos = getbe16(buf + cmd_pos + 2);
+#ifdef DEBUG
+        av_log(NULL, AV_LOG_INFO, "cmd_pos=0x%04x next=0x%04x date=%d\n", 
+               cmd_pos, next_cmd_pos, date);
+#endif
+        pos = cmd_pos + 4;
+        offset1 = -1;
+        offset2 = -1;
+        x1 = y1 = x2 = y2 = 0;
+        while (pos < buf_size) {
+            cmd = buf[pos++];
+#ifdef DEBUG
+            av_log(NULL, AV_LOG_INFO, "cmd=%02x\n", cmd);
+#endif
+            switch(cmd) {
+            case 0x00:
+                /* force display */
+                break;
+            case 0x01:
+                /* set start date */
+                sub_header->start_display_time = date * 10;
+                break;
+            case 0x02:
+                /* set end date */
+                sub_header->end_display_time = date * 10;
+                break;
+            case 0x03:
+                /* set palette */
+                if ((buf_size - pos) < 2)
+                    goto fail;
+                palette[0] = buf[pos] >> 4;
+                palette[1] = buf[pos] & 0x0f;
+                palette[2] = buf[pos + 1] >> 4;
+                palette[3] = buf[pos + 1] & 0x0f;
+                pos += 2;
+                break;
+            case 0x04:
+                /* set alpha */
+                if ((buf_size - pos) < 2)
+                    goto fail;
+                alpha[0] = buf[pos] >> 4;
+                alpha[1] = buf[pos] & 0x0f;
+                alpha[2] = buf[pos + 1] >> 4;
+                alpha[3] = buf[pos + 1] & 0x0f;
+                pos += 2;
+                break;
+            case 0x05:
+                if ((buf_size - pos) < 6)
+                    goto fail;
+                x1 = (buf[pos] << 4) | (buf[pos + 1] >> 4);
+                x2 = ((buf[pos + 1] & 0x0f) << 8) | buf[pos + 2];
+                y1 = (buf[pos + 3] << 4) | (buf[pos + 4] >> 4);
+                y2 = ((buf[pos + 4] & 0x0f) << 8) | buf[pos + 5];
+#ifdef DEBUG
+                av_log(NULL, AV_LOG_INFO, "x1=%d x2=%d y1=%d y2=%d\n",
+                       x1, x2, y1, y2);
+#endif
+                pos += 6;
+                break;
+            case 0x06:
+                if ((buf_size - pos) < 4)
+                    goto fail;
+                offset1 = getbe16(buf + pos);
+                offset2 = getbe16(buf + pos + 2);
+#ifdef DEBUG
+                av_log(NULL, AV_LOG_INFO, "offset1=0x%04x offset2=0x%04x\n", offset1, offset2);
+#endif
+                pos += 4;
+                break;
+            case 0xff:
+            default:
+                goto the_end;
+            }
+        }
+    the_end:
+        if (offset1 >= 0) {
+            int w, h;
+            uint8_t *bitmap;
+            
+            /* decode the bitmap */
+            w = x2 - x1 + 1;
+            if (w < 0)
+                w = 0;
+            h = y2 - y1;
+            if (h < 0)
+                h = 0;
+            if (w > 0 && h > 0) {
+                av_freep(&sub_header->bitmap);
+                av_freep(&sub_header->rgba_palette);
+                bitmap = av_malloc(w * h);
+                sub_header->rgba_palette = av_malloc(4 * 4);
+                decode_rle(bitmap, w * 2, w, h / 2,
+                           buf, offset1 * 2, buf_size);
+                decode_rle(bitmap + w, w * 2, w, h / 2,
+                           buf, offset2 * 2, buf_size);
+                guess_palette(sub_header->rgba_palette, 
+                              palette, alpha, 0xffff00);
+                sub_header->x = x1;
+                sub_header->y = y1;
+                sub_header->w = w;
+                sub_header->h = h;
+                sub_header->nb_colors = 4;
+                sub_header->linesize = w;
+                sub_header->bitmap = bitmap;
+            }
+        }
+        if (next_cmd_pos == cmd_pos)
+            break;
+        cmd_pos = next_cmd_pos;
+    }
+    if (sub_header->bitmap)
+        return 0;
+ fail:
+    return -1;
+}
+
+static int is_transp(const uint8_t *buf, int pitch, int n, 
+                     const uint8_t *transp_color)
+{
+    int i;
+    for(i = 0; i < n; i++) {
+        if (!transp_color[*buf])
+            return 0;
+        buf += pitch;
+    }
+    return 1;
+}
+
+/* return 0 if empty rectangle, 1 if non empty */
+static int find_smallest_bouding_rectangle(AVSubtitle *s)
+{
+    uint8_t transp_color[256];
+    int y1, y2, x1, x2, y, w, h, i;
+    uint8_t *bitmap;
+
+    if (s->w <= 0 || s->h <= 0)
+        return 0;
+
+    memset(transp_color, 0, 256);
+    for(i = 0; i < s->nb_colors; i++) {
+        if ((s->rgba_palette[i] >> 24) == 0)
+            transp_color[i] = 1;
+    }
+    y1 = 0;
+    while (y1 < s->h && is_transp(s->bitmap + y1 * s->linesize, 1, s->w, 
+                                  transp_color))
+        y1++;
+    if (y1 == s->h) {
+        av_freep(&s->bitmap);
+        s->w = s->h = 0;
+        return 0;
+    }
+
+    y2 = s->h - 1;
+    while (y2 > 0 && is_transp(s->bitmap + y2 * s->linesize, 1, s->w, 
+                               transp_color))
+        y2--;
+    x1 = 0;
+    while (x1 < (s->w - 1) && is_transp(s->bitmap + x1, s->linesize, s->h, 
+                                        transp_color))
+        x1++;
+    x2 = s->w - 1;
+    while (x2 > 0 && is_transp(s->bitmap + x2, s->linesize, s->h, 
+                                  transp_color))
+        x2--;
+    w = x2 - x1 + 1;
+    h = y2 - y1 + 1;
+    bitmap = av_malloc(w * h);
+    if (!bitmap)
+        return 1;
+    for(y = 0; y < h; y++) {
+        memcpy(bitmap + w * y, s->bitmap + x1 + (y1 + y) * s->linesize, w);
+    }
+    av_freep(&s->bitmap);
+    s->bitmap = bitmap;
+    s->linesize = w;
+    s->w = w;
+    s->h = h;
+    s->x += x1;
+    s->y += y1;
+    return 1;
+}
+
+static int dvdsub_close_decoder(AVCodecContext *avctx)
+{
+    return 0;
+}
+
+#ifdef DEBUG
+#undef fprintf
+static void ppm_save(const char *filename, uint8_t *bitmap, int w, int h,
+                     uint32_t *rgba_palette)
+{
+    int x, y, v;
+    FILE *f;
+
+    f = fopen(filename, "w");
+    if (!f) {
+        perror(filename);
+        exit(1);
+    }
+    fprintf(f, "P6\n"
+            "%d %d\n"
+            "%d\n",
+            w, h, 255);
+    for(y = 0; y < h; y++) {
+        for(x = 0; x < w; x++) {
+            v = rgba_palette[bitmap[y * w + x]];
+            putc((v >> 16) & 0xff, f);
+            putc((v >> 8) & 0xff, f);
+            putc((v >> 0) & 0xff, f);
+        }
+    }
+    fclose(f);
+}
+#endif
+
+static int dvdsub_decode(AVCodecContext *avctx,
+                         void *data, int *data_size,
+                         uint8_t *buf, int buf_size)
+{
+    AVSubtitle *sub = (void *)data;
+
+    if (decode_dvd_subtitles(sub, buf, buf_size) < 0) {
+    no_subtitle:
+        *data_size = 0;
+
+        return buf_size;
+    }
+    if (find_smallest_bouding_rectangle(sub) == 0)
+        goto no_subtitle;
+
+#if defined(DEBUG)
+    av_log(NULL, AV_LOG_INFO, "start=%d ms end =%d ms\n", 
+           sub->start_display_time,
+           sub->end_display_time);
+    ppm_save("/tmp/a.ppm", sub->bitmap, 
+             sub->w, sub->h, sub->rgba_palette);
+#endif
+
+    *data_size = 1;
+    return buf_size;
+}
+
+AVCodec dvdsub_decoder = {
+    "dvdsub",
+    CODEC_TYPE_SUBTITLE,
+    CODEC_ID_DVD_SUBTITLE,
+    sizeof(DVDSubContext),
+    dvdsub_init_decoder,
+    NULL,
+    dvdsub_close_decoder,
+    dvdsub_decode,
+};
+
+/* parser definition */
+typedef struct DVDSubParseContext {
+    uint8_t *packet;
+    int packet_len;
+    int packet_index;
+} DVDSubParseContext;
+
+static int dvdsub_parse_init(AVCodecParserContext *s)
+{
+    return 0;
+}
+
+static int dvdsub_parse(AVCodecParserContext *s,
+                        AVCodecContext *avctx,
+                        uint8_t **poutbuf, int *poutbuf_size, 
+                        const uint8_t *buf, int buf_size)
+{
+    DVDSubParseContext *pc = s->priv_data;
+    
+    if (pc->packet_index == 0) {
+        if (buf_size < 2)
+            return 0;
+        pc->packet_len = (buf[0] << 8) | buf[1];
+        av_freep(&pc->packet);
+        pc->packet = av_malloc(pc->packet_len);
+    }
+    if (pc->packet) {
+        if (pc->packet_index + buf_size <= pc->packet_len) {
+            memcpy(pc->packet + pc->packet_index, buf, buf_size);
+            pc->packet_index += buf_size;
+            if (pc->packet_index >= pc->packet_len) {
+                *poutbuf = pc->packet;
+                *poutbuf_size = pc->packet_len;
+                pc->packet_index = 0;
+                return buf_size;
+            }
+        } else {
+            /* erroneous size */
+            pc->packet_index = 0;
+        }
+    }
+    *poutbuf = NULL;
+    *poutbuf_size = 0;
+    return buf_size;
+}
+
+static void dvdsub_parse_close(AVCodecParserContext *s)
+{
+    DVDSubParseContext *pc = s->priv_data;
+    av_freep(&pc->packet);
+}
+
+AVCodecParser dvdsub_parser = {
+    { CODEC_ID_DVD_SUBTITLE },
+    sizeof(DVDSubParseContext),
+    dvdsub_parse_init,
+    dvdsub_parse,
+    dvdsub_parse_close,
+};