add SubRip encoder

Signed-off-by: Aurelien Jacobs <aurel@gnuage.org>

1 files changed, 301 insertions, 0 deletions

diff --git a/libavcodec/srtenc.c b/libavcodec/srtenc.c
new file mode 100644
index 0000000000..56d3397828
--- /dev/null
+++ b/libavcodec/srtenc.c
@@ -0,0 +1,301 @@
+/*
+ * SubRip subtitle encoder
+ * Copyright (c) 2010  Aurelien Jacobs <aurel@gnuage.org>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <stdarg.h>
+#include "avcodec.h"
+#include "libavutil/avstring.h"
+#include "ass_split.h"
+#include "ass.h"
+
+
+#define SRT_STACK_SIZE 64
+
+typedef struct {
+    AVCodecContext *avctx;
+    ASSSplitContext *ass_ctx;
+    char buffer[2048];
+    char *ptr;
+    char *end;
+    char *dialog_start;
+    int count;
+    char stack[SRT_STACK_SIZE];
+    int stack_ptr;
+    int alignment_applied;
+} SRTContext;
+
+
+#ifdef __GNUC__
+__attribute__ ((__format__ (__printf__, 2, 3)))
+#endif
+static void srt_print(SRTContext *s, const char *str, ...)
+{
+    va_list vargs;
+    va_start(vargs, str);
+    s->ptr += vsnprintf(s->ptr, s->end - s->ptr, str, vargs);
+    va_end(vargs);
+}
+
+static int srt_stack_push(SRTContext *s, const char c)
+{
+    if (s->stack_ptr >= SRT_STACK_SIZE)
+        return -1;
+    s->stack[s->stack_ptr++] = c;
+    return 0;
+}
+
+static char srt_stack_pop(SRTContext *s)
+{
+    if (s->stack_ptr <= 0)
+        return 0;
+    return s->stack[--s->stack_ptr];
+}
+
+static int srt_stack_find(SRTContext *s, const char c)
+{
+    int i;
+    for (i = s->stack_ptr-1; i >= 0; i--)
+        if (s->stack[i] == c)
+            break;
+    return i;
+}
+
+static void srt_close_tag(SRTContext *s, char tag)
+{
+    srt_print(s, "</%c%s>", tag, tag == 'f' ? "ont" : "");
+}
+
+static void srt_stack_push_pop(SRTContext *s, const char c, int close)
+{
+    if (close) {
+        int i = c ? srt_stack_find(s, c) : 0;
+        if (i < 0)
+            return;
+        while (s->stack_ptr != i)
+            srt_close_tag(s, srt_stack_pop(s));
+    } else if (srt_stack_push(s, c) < 0)
+        av_log(s->avctx, AV_LOG_ERROR, "tag stack overflow\n");
+}
+
+static void srt_style_apply(SRTContext *s, const char *style)
+{
+    ASSStyle *st = ass_style_get(s->ass_ctx, style);
+    if (st) {
+        int c = st->primary_color & 0xFFFFFF;
+        if (st->font_name && strcmp(st->font_name, ASS_DEFAULT_FONT) ||
+            st->font_size != ASS_DEFAULT_FONT_SIZE ||
+            c != ASS_DEFAULT_COLOR) {
+            srt_print(s, "<font");
+            if (st->font_name && strcmp(st->font_name, ASS_DEFAULT_FONT))
+                srt_print(s, " face=\"%s\"", st->font_name);
+            if (st->font_size != ASS_DEFAULT_FONT_SIZE)
+                srt_print(s, " size=\"%d\"", st->font_size);
+            if (c != ASS_DEFAULT_COLOR)
+                srt_print(s, " color=\"#%06x\"",
+                          (c & 0xFF0000) >> 16 | c & 0xFF00 | (c & 0xFF) << 16);
+            srt_print(s, ">");
+            srt_stack_push(s, 'f');
+        }
+        if (st->bold != ASS_DEFAULT_BOLD) {
+            srt_print(s, "<b>");
+            srt_stack_push(s, 'b');
+        }
+        if (st->italic != ASS_DEFAULT_ITALIC) {
+            srt_print(s, "<i>");
+            srt_stack_push(s, 'i');
+        }
+        if (st->underline != ASS_DEFAULT_UNDERLINE) {
+            srt_print(s, "<u>");
+            srt_stack_push(s, 'u');
+        }
+        if (st->alignment != ASS_DEFAULT_ALIGNMENT) {
+            srt_print(s, "{\\an%d}", st->alignment);
+            s->alignment_applied = 1;
+        }
+    }
+}
+
+
+static av_cold int srt_encode_init(AVCodecContext *avctx)
+{
+    SRTContext *s = avctx->priv_data;
+    s->avctx = avctx;
+    s->ass_ctx = ff_ass_split(avctx->subtitle_header);
+    return s->ass_ctx ? 0 : AVERROR_INVALIDDATA;
+}
+
+static void srt_text_cb(void *priv, const char *text, int len)
+{
+    SRTContext *s = priv;
+    av_strlcpy(s->ptr, text, FFMIN(s->end-s->ptr, len+1));
+    s->ptr += len;
+}
+
+static void srt_new_line_cb(void *priv, int forced)
+{
+    srt_print(priv, "\r\n");
+}
+
+static void srt_style_cb(void *priv, char style, int close)
+{
+    srt_stack_push_pop(priv, style, close);
+    if (!close)
+        srt_print(priv, "<%c>", style);
+}
+
+static void srt_color_cb(void *priv, unsigned int color, unsigned int color_id)
+{
+    if (color_id > 1)
+        return;
+    srt_stack_push_pop(priv, 'f', color == 0xFFFFFFFF);
+    if (color != 0xFFFFFFFF)
+        srt_print(priv, "<font color=\"#%06x\">",
+              (color & 0xFF0000) >> 16 | color & 0xFF00 | (color & 0xFF) << 16);
+}
+
+static void srt_font_name_cb(void *priv, const char *name)
+{
+    srt_stack_push_pop(priv, 'f', !name);
+    if (name)
+        srt_print(priv, "<font face=\"%s\">", name);
+}
+
+static void srt_font_size_cb(void *priv, int size)
+{
+    srt_stack_push_pop(priv, 'f', size < 0);
+    if (size >= 0)
+        srt_print(priv, "<font size=\"%d\">", size);
+}
+
+static void srt_alignment_cb(void *priv, int alignment)
+{
+    SRTContext *s = priv;
+    if (!s->alignment_applied && alignment >= 0) {
+        srt_print(s, "{\\an%d}", alignment);
+        s->alignment_applied = 1;
+    }
+}
+
+static void srt_cancel_overrides_cb(void *priv, const char *style)
+{
+    srt_stack_push_pop(priv, 0, 1);
+    srt_style_apply(priv, style);
+}
+
+static void srt_move_cb(void *priv, int x1, int y1, int x2, int y2,
+                        int t1, int t2)
+{
+    SRTContext *s = priv;
+    char buffer[32];
+    int len = snprintf(buffer, sizeof(buffer),
+                       "  X1:%03u X2:%03u Y1:%03u Y2:%03u", x1, x2, y1, y2);
+    if (s->end - s->ptr > len) {
+        memmove(s->dialog_start+len, s->dialog_start, s->ptr-s->dialog_start+1);
+        memcpy(s->dialog_start, buffer, len);
+        s->ptr += len;
+    }
+}
+
+static void srt_end_cb(void *priv)
+{
+    srt_stack_push_pop(priv, 0, 1);
+    srt_print(priv, "\r\n\r\n");
+}
+
+static const ASSCodesCallbacks srt_callbacks = {
+    .text             = srt_text_cb,
+    .new_line         = srt_new_line_cb,
+    .style            = srt_style_cb,
+    .color            = srt_color_cb,
+    .font_name        = srt_font_name_cb,
+    .font_size        = srt_font_size_cb,
+    .alignment        = srt_alignment_cb,
+    .cancel_overrides = srt_cancel_overrides_cb,
+    .move             = srt_move_cb,
+    .end              = srt_end_cb,
+};
+
+static int srt_encode_frame(AVCodecContext *avctx,
+                            unsigned char *buf, int bufsize, void *data)
+{
+    SRTContext *s = avctx->priv_data;
+    AVSubtitle *sub = data;
+    ASSDialog *dialog;
+    int i, len, num;
+
+    s->ptr = s->buffer;
+    s->end = s->ptr + sizeof(s->buffer);
+
+    for (i=0; i<sub->num_rects; i++) {
+
+        if (sub->rects[i]->type != SUBTITLE_ASS) {
+            av_log(avctx, AV_LOG_ERROR, "Only SUBTITLE_ASS type supported.\n");
+            return AVERROR(ENOSYS);
+        }
+
+        dialog = ff_ass_split_dialog(s->ass_ctx, sub->rects[i]->ass, 0, &num);
+        for (; dialog && num--; dialog++) {
+            int sh, sm, ss, sc = 10 * dialog->start;
+            int eh, em, es, ec = 10 * dialog->end;
+            sh = sc/3600000;  sc -= 3600000*sh;
+            sm = sc/  60000;  sc -=   60000*sm;
+            ss = sc/   1000;  sc -=    1000*ss;
+            eh = ec/3600000;  ec -= 3600000*eh;
+            em = ec/  60000;  ec -=   60000*em;
+            es = ec/   1000;  ec -=    1000*es;
+            srt_print(s,"%d\r\n%02d:%02d:%02d,%03d --> %02d:%02d:%02d,%03d\r\n",
+                      ++s->count, sh, sm, ss, sc, eh, em, es, ec);
+            s->alignment_applied = 0;
+            s->dialog_start = s->ptr - 2;
+            srt_style_apply(s, dialog->style);
+            ff_ass_split_override_codes(&srt_callbacks, s, dialog->text);
+        }
+    }
+
+    if (s->ptr == s->buffer)
+        return 0;
+
+    len = av_strlcpy(buf, s->buffer, bufsize);
+
+    if (len > bufsize-1) {
+        av_log(avctx, AV_LOG_ERROR, "Buffer too small for ASS event.\n");
+        return -1;
+    }
+
+    return len;
+}
+
+static int srt_encode_close(AVCodecContext *avctx)
+{
+    SRTContext *s = avctx->priv_data;
+    ff_ass_split_free(s->ass_ctx);
+    return 0;
+}
+
+AVCodec ff_srt_encoder = {
+    .name           = "srt",
+    .long_name      = NULL_IF_CONFIG_SMALL("SubRip subtitle"),
+    .type           = AVMEDIA_TYPE_SUBTITLE,
+    .id             = CODEC_ID_SRT,
+    .priv_data_size = sizeof(SRTContext),
+    .init           = srt_encode_init,
+    .encode         = srt_encode_frame,
+    .close          = srt_encode_close,
+};