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-rw-r--r--libavcodec/movtextdec.c605
1 files changed, 605 insertions, 0 deletions
diff --git a/libavcodec/movtextdec.c b/libavcodec/movtextdec.c
new file mode 100644
index 0000000000..f799252bf2
--- /dev/null
+++ b/libavcodec/movtextdec.c
@@ -0,0 +1,605 @@
+/*
+ * 3GPP TS 26.245 Timed Text decoder
+ * Copyright (c) 2012 Philip Langdale <philipl@overt.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 "avcodec.h"
+#include "ass.h"
+#include "libavutil/opt.h"
+#include "libavutil/avstring.h"
+#include "libavutil/common.h"
+#include "libavutil/bprint.h"
+#include "libavutil/intreadwrite.h"
+#include "libavutil/mem.h"
+#include "bytestream.h"
+#include "codec_internal.h"
+
+#define STYLE_FLAG_BOLD (1<<0)
+#define STYLE_FLAG_ITALIC (1<<1)
+#define STYLE_FLAG_UNDERLINE (1<<2)
+
+#define BOX_SIZE_INITIAL 40
+
+#define STYL_BOX (1<<0)
+#define HLIT_BOX (1<<1)
+#define HCLR_BOX (1<<2)
+#define TWRP_BOX (1<<3)
+
+#define BOTTOM_LEFT 1
+#define BOTTOM_CENTER 2
+#define BOTTOM_RIGHT 3
+#define MIDDLE_LEFT 4
+#define MIDDLE_CENTER 5
+#define MIDDLE_RIGHT 6
+#define TOP_LEFT 7
+#define TOP_CENTER 8
+#define TOP_RIGHT 9
+
+#define RGB_TO_BGR(c) (((c) & 0xff) << 16 | ((c) & 0xff00) | (((c) >> 16) & 0xff))
+
+typedef struct {
+ uint16_t font_id;
+ char *font;
+} FontRecord;
+
+typedef struct {
+ uint16_t start;
+ uint16_t end;
+ uint8_t flags;
+ uint8_t bold;
+ uint8_t italic;
+ uint8_t underline;
+ int color;
+ uint8_t alpha;
+ uint8_t fontsize;
+ uint16_t font_id;
+} StyleBox;
+
+typedef struct {
+ StyleBox style;
+ const char *font;
+ int back_color;
+ uint8_t back_alpha;
+ int alignment;
+} MovTextDefault;
+
+typedef struct {
+ uint16_t hlit_start;
+ uint16_t hlit_end;
+} HighlightBox;
+
+typedef struct {
+ uint8_t hlit_color[4];
+} HilightcolorBox;
+
+typedef struct {
+ uint8_t wrap_flag;
+} TextWrapBox;
+
+typedef struct {
+ AVClass *class;
+ StyleBox *s;
+ HighlightBox h;
+ HilightcolorBox c;
+ FontRecord *ftab;
+ TextWrapBox w;
+ MovTextDefault d;
+ uint8_t box_flags;
+ uint16_t style_entries, ftab_entries;
+ int readorder;
+ int frame_width;
+ int frame_height;
+} MovTextContext;
+
+typedef struct {
+ uint32_t type;
+ unsigned base_size;
+ int (*decode)(const uint8_t *tsmb, MovTextContext *m, uint64_t size);
+} Box;
+
+static void mov_text_cleanup(MovTextContext *m)
+{
+ if (m->box_flags & STYL_BOX) {
+ av_freep(&m->s);
+ m->style_entries = 0;
+ }
+}
+
+static void mov_text_cleanup_ftab(MovTextContext *m)
+{
+ for (unsigned i = 0; i < m->ftab_entries; i++)
+ av_freep(&m->ftab[i].font);
+ av_freep(&m->ftab);
+ m->ftab_entries = 0;
+}
+
+static void mov_text_parse_style_record(StyleBox *style, const uint8_t **ptr)
+{
+ // fontID
+ style->font_id = bytestream_get_be16(ptr);
+ // face-style-flags
+ style->flags = bytestream_get_byte(ptr);
+ style->bold = !!(style->flags & STYLE_FLAG_BOLD);
+ style->italic = !!(style->flags & STYLE_FLAG_ITALIC);
+ style->underline = !!(style->flags & STYLE_FLAG_UNDERLINE);
+ // fontsize
+ style->fontsize = bytestream_get_byte(ptr);
+ // Primary color
+ style->color = bytestream_get_be24(ptr);
+ style->color = RGB_TO_BGR(style->color);
+ style->alpha = bytestream_get_byte(ptr);
+}
+
+static int mov_text_tx3g(AVCodecContext *avctx, MovTextContext *m)
+{
+ const uint8_t *tx3g_ptr = avctx->extradata;
+ int i, j = -1, font_length, remaining = avctx->extradata_size - BOX_SIZE_INITIAL;
+ int8_t v_align, h_align;
+ unsigned ftab_entries;
+
+ m->ftab_entries = 0;
+ if (remaining < 0)
+ return -1;
+
+ // Display Flags
+ tx3g_ptr += 4;
+ // Alignment
+ h_align = bytestream_get_byte(&tx3g_ptr);
+ v_align = bytestream_get_byte(&tx3g_ptr);
+ if (h_align == 0) {
+ if (v_align == 0)
+ m->d.alignment = TOP_LEFT;
+ if (v_align == 1)
+ m->d.alignment = MIDDLE_LEFT;
+ if (v_align == -1)
+ m->d.alignment = BOTTOM_LEFT;
+ }
+ if (h_align == 1) {
+ if (v_align == 0)
+ m->d.alignment = TOP_CENTER;
+ if (v_align == 1)
+ m->d.alignment = MIDDLE_CENTER;
+ if (v_align == -1)
+ m->d.alignment = BOTTOM_CENTER;
+ }
+ if (h_align == -1) {
+ if (v_align == 0)
+ m->d.alignment = TOP_RIGHT;
+ if (v_align == 1)
+ m->d.alignment = MIDDLE_RIGHT;
+ if (v_align == -1)
+ m->d.alignment = BOTTOM_RIGHT;
+ }
+ // Background Color
+ m->d.back_color = bytestream_get_be24(&tx3g_ptr);
+ m->d.back_color = RGB_TO_BGR(m->d.back_color);
+ m->d.back_alpha = bytestream_get_byte(&tx3g_ptr);
+ // BoxRecord
+ tx3g_ptr += 8;
+ // StyleRecord
+ tx3g_ptr += 4;
+ mov_text_parse_style_record(&m->d.style, &tx3g_ptr);
+ // FontRecord
+ // FontRecord Size
+ tx3g_ptr += 4;
+ // ftab
+ tx3g_ptr += 4;
+
+ // In case of broken header, init default font
+ m->d.font = ASS_DEFAULT_FONT;
+
+ ftab_entries = bytestream_get_be16(&tx3g_ptr);
+ if (!ftab_entries)
+ return 0;
+ remaining -= 3 * ftab_entries;
+ if (remaining < 0)
+ return AVERROR_INVALIDDATA;
+ m->ftab = av_calloc(ftab_entries, sizeof(*m->ftab));
+ if (!m->ftab)
+ return AVERROR(ENOMEM);
+ m->ftab_entries = ftab_entries;
+
+ for (i = 0; i < m->ftab_entries; i++) {
+ m->ftab[i].font_id = bytestream_get_be16(&tx3g_ptr);
+ if (m->ftab[i].font_id == m->d.style.font_id)
+ j = i;
+ font_length = bytestream_get_byte(&tx3g_ptr);
+
+ remaining -= font_length;
+ if (remaining < 0) {
+ mov_text_cleanup_ftab(m);
+ return -1;
+ }
+ m->ftab[i].font = av_malloc(font_length + 1);
+ if (!m->ftab[i].font) {
+ mov_text_cleanup_ftab(m);
+ return AVERROR(ENOMEM);
+ }
+ bytestream_get_buffer(&tx3g_ptr, m->ftab[i].font, font_length);
+ m->ftab[i].font[font_length] = '\0';
+ }
+ if (j >= 0)
+ m->d.font = m->ftab[j].font;
+ return 0;
+}
+
+static int decode_twrp(const uint8_t *tsmb, MovTextContext *m, uint64_t size)
+{
+ m->box_flags |= TWRP_BOX;
+ m->w.wrap_flag = bytestream_get_byte(&tsmb);
+ return 0;
+}
+
+static int decode_hlit(const uint8_t *tsmb, MovTextContext *m, uint64_t size)
+{
+ m->box_flags |= HLIT_BOX;
+ m->h.hlit_start = bytestream_get_be16(&tsmb);
+ m->h.hlit_end = bytestream_get_be16(&tsmb);
+ return 0;
+}
+
+static int decode_hclr(const uint8_t *tsmb, MovTextContext *m, uint64_t size)
+{
+ m->box_flags |= HCLR_BOX;
+ bytestream_get_buffer(&tsmb, m->c.hlit_color, 4);
+ return 0;
+}
+
+static int styles_equivalent(const StyleBox *a, const StyleBox *b)
+{
+#define CMP(field) ((a)->field == (b)->field)
+ return CMP(bold) && CMP(italic) && CMP(underline) && CMP(color) &&
+ CMP(alpha) && CMP(fontsize) && CMP(font_id);
+#undef CMP
+}
+
+static int decode_styl(const uint8_t *tsmb, MovTextContext *m, uint64_t size)
+{
+ int i;
+ int style_entries = bytestream_get_be16(&tsmb);
+ StyleBox *tmp;
+
+ // A single style record is of length 12 bytes.
+ if (2 + style_entries * 12 > size)
+ return -1;
+
+ tmp = av_realloc_array(m->s, style_entries, sizeof(*m->s));
+ if (!tmp)
+ return AVERROR(ENOMEM);
+ m->s = tmp;
+ m->style_entries = style_entries;
+
+ m->box_flags |= STYL_BOX;
+ for(i = 0; i < m->style_entries; i++) {
+ StyleBox *style = &m->s[i];
+
+ style->start = bytestream_get_be16(&tsmb);
+ style->end = bytestream_get_be16(&tsmb);
+ if (style->end < style->start ||
+ (i && style->start < m->s[i - 1].end)) {
+ mov_text_cleanup(m);
+ return AVERROR_INVALIDDATA;
+ }
+ if (style->start == style->end) {
+ /* Skip this style as it applies to no character */
+ tsmb += 8;
+ m->style_entries--;
+ i--;
+ continue;
+ }
+
+ mov_text_parse_style_record(style, &tsmb);
+ if (styles_equivalent(style, &m->d.style)) {
+ /* Skip this style as it is equivalent to the default style */
+ m->style_entries--;
+ i--;
+ continue;
+ } else if (i && style->start == style[-1].end &&
+ styles_equivalent(style, &style[-1])) {
+ /* Merge the two adjacent styles */
+ style[-1].end = style->end;
+ m->style_entries--;
+ i--;
+ continue;
+ }
+ }
+ return 0;
+}
+
+static const Box box_types[] = {
+ { MKBETAG('s','t','y','l'), 2, decode_styl },
+ { MKBETAG('h','l','i','t'), 4, decode_hlit },
+ { MKBETAG('h','c','l','r'), 4, decode_hclr },
+ { MKBETAG('t','w','r','p'), 1, decode_twrp }
+};
+
+const static size_t box_count = FF_ARRAY_ELEMS(box_types);
+
+// Return byte length of the UTF-8 sequence starting at text[0]. 0 on error.
+static int get_utf8_length_at(const char *text, const char *text_end)
+{
+ const char *start = text;
+ int err = 0;
+ uint32_t c;
+ GET_UTF8(c, text < text_end ? (uint8_t)*text++ : (err = 1, 0), goto error;);
+ if (err)
+ goto error;
+ return text - start;
+error:
+ return 0;
+}
+
+static int text_to_ass(AVBPrint *buf, const char *text, const char *text_end,
+ AVCodecContext *avctx)
+{
+ MovTextContext *m = avctx->priv_data;
+ const StyleBox *const default_style = &m->d.style;
+ int i = 0;
+ int text_pos = 0;
+ int entry = 0;
+ int color = default_style->color;
+
+ if (text < text_end && m->box_flags & TWRP_BOX) {
+ if (m->w.wrap_flag == 1) {
+ av_bprintf(buf, "{\\q1}"); /* End of line wrap */
+ } else {
+ av_bprintf(buf, "{\\q2}"); /* No wrap */
+ }
+ }
+
+ while (text < text_end) {
+ int len;
+
+ if ((m->box_flags & STYL_BOX) && entry < m->style_entries) {
+ const StyleBox *style = &m->s[entry];
+ if (text_pos == style->end) {
+ av_bprintf(buf, "{\\r}");
+ color = default_style->color;
+ entry++;
+ style++;
+ }
+ if (entry < m->style_entries && text_pos == style->start) {
+ if (style->bold ^ default_style->bold)
+ av_bprintf(buf, "{\\b%d}", style->bold);
+ if (style->italic ^ default_style->italic)
+ av_bprintf(buf, "{\\i%d}", style->italic);
+ if (style->underline ^ default_style->underline)
+ av_bprintf(buf, "{\\u%d}", style->underline);
+ if (style->fontsize != default_style->fontsize)
+ av_bprintf(buf, "{\\fs%d}", style->fontsize);
+ if (style->font_id != default_style->font_id)
+ for (i = 0; i < m->ftab_entries; i++) {
+ if (style->font_id == m->ftab[i].font_id)
+ av_bprintf(buf, "{\\fn%s}", m->ftab[i].font);
+ }
+ if (default_style->color != style->color) {
+ color = style->color;
+ av_bprintf(buf, "{\\1c&H%X&}", color);
+ }
+ if (default_style->alpha != style->alpha)
+ av_bprintf(buf, "{\\1a&H%02X&}", 255 - style->alpha);
+ }
+ }
+ if (m->box_flags & HLIT_BOX) {
+ if (text_pos == m->h.hlit_start) {
+ /* If hclr box is present, set the secondary color to the color
+ * specified. Otherwise, set primary color to white and secondary
+ * color to black. These colors will come from TextSampleModifier
+ * boxes in future and inverse video technique for highlight will
+ * be implemented.
+ */
+ if (m->box_flags & HCLR_BOX) {
+ av_bprintf(buf, "{\\2c&H%02x%02x%02x&}", m->c.hlit_color[2],
+ m->c.hlit_color[1], m->c.hlit_color[0]);
+ } else {
+ av_bprintf(buf, "{\\1c&H000000&}{\\2c&HFFFFFF&}");
+ }
+ }
+ if (text_pos == m->h.hlit_end) {
+ if (m->box_flags & HCLR_BOX) {
+ av_bprintf(buf, "{\\2c&H%X&}", default_style->color);
+ } else {
+ av_bprintf(buf, "{\\1c&H%X&}{\\2c&H%X&}",
+ color, default_style->color);
+ }
+ }
+ }
+
+ len = get_utf8_length_at(text, text_end);
+ if (len < 1) {
+ av_log(avctx, AV_LOG_ERROR, "invalid UTF-8 byte in subtitle\n");
+ len = 1;
+ }
+ switch (*text) {
+ case '\r':
+ break;
+ case '\n':
+ av_bprintf(buf, "\\N");
+ break;
+ default:
+ av_bprint_append_data(buf, text, len);
+ break;
+ }
+ text += len;
+ text_pos++;
+ }
+
+ return 0;
+}
+
+static int mov_text_init(AVCodecContext *avctx) {
+ /*
+ * TODO: Handle the default text style.
+ * NB: Most players ignore styles completely, with the result that
+ * it's very common to find files where the default style is broken
+ * and respecting it results in a worse experience than ignoring it.
+ */
+ int ret;
+ MovTextContext *m = avctx->priv_data;
+ ret = mov_text_tx3g(avctx, m);
+ if (ret == 0) {
+ const StyleBox *const default_style = &m->d.style;
+ if (!m->frame_width || !m->frame_height) {
+ m->frame_width = ASS_DEFAULT_PLAYRESX;
+ m->frame_height = ASS_DEFAULT_PLAYRESY;
+ }
+ return ff_ass_subtitle_header_full(avctx,
+ m->frame_width, m->frame_height,
+ m->d.font, default_style->fontsize,
+ (255U - default_style->alpha) << 24 | default_style->color,
+ (255U - default_style->alpha) << 24 | default_style->color,
+ (255U - m->d.back_alpha) << 24 | m->d.back_color,
+ (255U - m->d.back_alpha) << 24 | m->d.back_color,
+ default_style->bold, default_style->italic, default_style->underline,
+ ASS_DEFAULT_BORDERSTYLE, m->d.alignment);
+ } else
+ return ff_ass_subtitle_header_default(avctx);
+}
+
+static int mov_text_decode_frame(AVCodecContext *avctx, AVSubtitle *sub,
+ int *got_sub_ptr, const AVPacket *avpkt)
+{
+ MovTextContext *m = avctx->priv_data;
+ int ret;
+ AVBPrint buf;
+ const char *ptr = avpkt->data, *end;
+ int text_length;
+ size_t i;
+
+ if (!ptr || avpkt->size < 2)
+ return AVERROR_INVALIDDATA;
+
+ /*
+ * A packet of size two with value zero is an empty subtitle
+ * used to mark the end of the previous non-empty subtitle.
+ * We can just drop them here as we have duration information
+ * already. If the value is non-zero, then it's technically a
+ * bad packet.
+ */
+ if (avpkt->size == 2)
+ return AV_RB16(ptr) == 0 ? 0 : AVERROR_INVALIDDATA;
+
+ /*
+ * The first two bytes of the packet are the length of the text string
+ * In complex cases, there are style descriptors appended to the string
+ * so we can't just assume the packet size is the string size.
+ */
+ text_length = AV_RB16(ptr);
+ end = ptr + FFMIN(2 + text_length, avpkt->size);
+ ptr += 2;
+
+ mov_text_cleanup(m);
+
+ m->style_entries = 0;
+ m->box_flags = 0;
+ // Note that the spec recommends lines be no longer than 2048 characters.
+ av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
+ if (text_length + 2 < avpkt->size) {
+ const uint8_t *tsmb = end;
+ const uint8_t *const tsmb_end = avpkt->data + avpkt->size;
+ // A box is a minimum of 8 bytes.
+ while (tsmb_end - tsmb >= 8) {
+ uint64_t tsmb_size = bytestream_get_be32(&tsmb);
+ uint32_t tsmb_type = bytestream_get_be32(&tsmb);
+ int size_var, ret_tsmb;
+
+ if (tsmb_size == 1) {
+ if (tsmb_end - tsmb < 8)
+ break;
+ tsmb_size = bytestream_get_be64(&tsmb);
+ size_var = 16;
+ } else
+ size_var = 8;
+ //size_var is equal to 8 or 16 depending on the size of box
+
+ if (tsmb_size < size_var) {
+ av_log(avctx, AV_LOG_ERROR, "tsmb_size invalid\n");
+ return AVERROR_INVALIDDATA;
+ }
+ tsmb_size -= size_var;
+
+ if (tsmb_end - tsmb < tsmb_size)
+ break;
+
+ for (i = 0; i < box_count; i++) {
+ if (tsmb_type == box_types[i].type) {
+ if (tsmb_size < box_types[i].base_size)
+ break;
+ ret_tsmb = box_types[i].decode(tsmb, m, tsmb_size);
+ if (ret_tsmb == -1)
+ break;
+ }
+ }
+ tsmb += tsmb_size;
+ }
+ text_to_ass(&buf, ptr, end, avctx);
+ mov_text_cleanup(m);
+ } else
+ text_to_ass(&buf, ptr, end, avctx);
+
+ ret = ff_ass_add_rect(sub, buf.str, m->readorder++, 0, NULL, NULL);
+ av_bprint_finalize(&buf, NULL);
+ if (ret < 0)
+ return ret;
+ *got_sub_ptr = sub->num_rects > 0;
+ return avpkt->size;
+}
+
+static int mov_text_decode_close(AVCodecContext *avctx)
+{
+ MovTextContext *m = avctx->priv_data;
+ mov_text_cleanup_ftab(m);
+ mov_text_cleanup(m);
+ return 0;
+}
+
+static void mov_text_flush(AVCodecContext *avctx)
+{
+ MovTextContext *m = avctx->priv_data;
+ if (!(avctx->flags2 & AV_CODEC_FLAG2_RO_FLUSH_NOOP))
+ m->readorder = 0;
+}
+
+#define OFFSET(x) offsetof(MovTextContext, x)
+#define FLAGS AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_SUBTITLE_PARAM
+static const AVOption options[] = {
+ { "width", "Frame width, usually video width", OFFSET(frame_width), AV_OPT_TYPE_INT, {.i64=0}, 0, INT_MAX, FLAGS },
+ { "height", "Frame height, usually video height", OFFSET(frame_height), AV_OPT_TYPE_INT, {.i64=0}, 0, INT_MAX, FLAGS },
+ { NULL },
+};
+
+static const AVClass mov_text_decoder_class = {
+ .class_name = "MOV text decoder",
+ .item_name = av_default_item_name,
+ .option = options,
+ .version = LIBAVUTIL_VERSION_INT,
+};
+
+const FFCodec ff_movtext_decoder = {
+ .p.name = "mov_text",
+ CODEC_LONG_NAME("3GPP Timed Text subtitle"),
+ .p.type = AVMEDIA_TYPE_SUBTITLE,
+ .p.id = AV_CODEC_ID_MOV_TEXT,
+ .priv_data_size = sizeof(MovTextContext),
+ .p.priv_class = &mov_text_decoder_class,
+ .init = mov_text_init,
+ FF_CODEC_DECODE_SUB_CB(mov_text_decode_frame),
+ .close = mov_text_decode_close,
+ .flush = mov_text_flush,
+};
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-25 18:17:55 +0000