diff options
Diffstat (limited to 'libavcodec/movtextdec.c')
| -rw-r--r-- | libavcodec/movtextdec.c | 324 |
1 files changed, 324 insertions, 0 deletions
diff --git a/libavcodec/movtextdec.c b/libavcodec/movtextdec.c new file mode 100644 index 0000000000..869358cb91 --- /dev/null +++ b/libavcodec/movtextdec.c @@ -0,0 +1,324 @@ +/* + * 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/avstring.h" +#include "libavutil/common.h" +#include "libavutil/bprint.h" +#include "libavutil/intreadwrite.h" +#include "libavutil/mem.h" + +#define STYLE_FLAG_BOLD (1<<0) +#define STYLE_FLAG_ITALIC (1<<1) +#define STYLE_FLAG_UNDERLINE (1<<2) + +#define STYL_BOX (1<<0) +#define HLIT_BOX (1<<1) +#define HCLR_BOX (1<<2) + +typedef struct { + uint16_t style_start; + uint16_t style_end; + uint8_t style_flag; + uint8_t fontsize; +} StyleBox; + +typedef struct { + uint16_t hlit_start; + uint16_t hlit_end; +} HighlightBox; + +typedef struct { + uint8_t hlit_color[4]; +} HilightcolorBox; + +typedef struct { + StyleBox **s; + StyleBox *s_temp; + HighlightBox h; + HilightcolorBox c; + uint8_t box_flags; + uint16_t style_entries; + uint64_t tracksize; + int size_var; + int count_s; +} MovTextContext; + +typedef struct { + uint32_t type; + size_t base_size; + int (*decode)(const uint8_t *tsmb, MovTextContext *m, AVPacket *avpkt); +} Box; + +static void mov_text_cleanup(MovTextContext *m) +{ + int i; + if (m->box_flags & STYL_BOX) { + for(i = 0; i < m->count_s; i++) { + av_freep(&m->s[i]); + } + av_freep(&m->s); + } +} + +static int decode_hlit(const uint8_t *tsmb, MovTextContext *m, AVPacket *avpkt) +{ + m->box_flags |= HLIT_BOX; + m->h.hlit_start = AV_RB16(tsmb); + tsmb += 2; + m->h.hlit_end = AV_RB16(tsmb); + tsmb += 2; + return 0; +} + +static int decode_hclr(const uint8_t *tsmb, MovTextContext *m, AVPacket *avpkt) +{ + m->box_flags |= HCLR_BOX; + memcpy(m->c.hlit_color, tsmb, 4); + tsmb += 4; + return 0; +} + +static int decode_styl(const uint8_t *tsmb, MovTextContext *m, AVPacket *avpkt) +{ + int i; + m->style_entries = AV_RB16(tsmb); + tsmb += 2; + // A single style record is of length 12 bytes. + if (m->tracksize + m->size_var + 2 + m->style_entries * 12 > avpkt->size) + return -1; + + m->box_flags |= STYL_BOX; + for(i = 0; i < m->style_entries; i++) { + m->s_temp = av_malloc(sizeof(*m->s_temp)); + if (!m->s_temp) { + mov_text_cleanup(m); + return AVERROR(ENOMEM); + } + m->s_temp->style_start = AV_RB16(tsmb); + tsmb += 2; + m->s_temp->style_end = AV_RB16(tsmb); + tsmb += 2; + // fontID = AV_RB16(tsmb); + tsmb += 2; + m->s_temp->style_flag = AV_RB8(tsmb); + tsmb++; + m->s_temp->fontsize = AV_RB8(tsmb); + av_dynarray_add(&m->s, &m->count_s, m->s_temp); + if(!m->s) { + mov_text_cleanup(m); + return AVERROR(ENOMEM); + } + tsmb++; + // text-color-rgba + tsmb += 4; + } + 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 } +}; + +const static size_t box_count = FF_ARRAY_ELEMS(box_types); + +static int text_to_ass(AVBPrint *buf, const char *text, const char *text_end, + MovTextContext *m) +{ + int i = 0; + int text_pos = 0; + while (text < text_end) { + if (m->box_flags & STYL_BOX) { + for (i = 0; i < m->style_entries; i++) { + if (m->s[i]->style_flag && text_pos == m->s[i]->style_end) { + av_bprintf(buf, "{\\r}"); + } + } + for (i = 0; i < m->style_entries; i++) { + if (m->s[i]->style_flag && text_pos == m->s[i]->style_start) { + if (m->s[i]->style_flag & STYLE_FLAG_BOLD) + av_bprintf(buf, "{\\b1}"); + if (m->s[i]->style_flag & STYLE_FLAG_ITALIC) + av_bprintf(buf, "{\\i1}"); + if (m->s[i]->style_flag & STYLE_FLAG_UNDERLINE) + av_bprintf(buf, "{\\u1}"); + av_bprintf(buf, "{\\fs%d}", m->s[i]->fontsize); + } + } + } + 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&H000000&}"); + } else { + av_bprintf(buf, "{\\1c&HFFFFFF&}{\\2c&H000000&}"); + } + } + } + + switch (*text) { + case '\r': + break; + case '\n': + av_bprintf(buf, "\\N"); + break; + default: + av_bprint_chars(buf, *text, 1); + break; + } + text++; + 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. + */ + return ff_ass_subtitle_header_default(avctx); +} + +static int mov_text_decode_frame(AVCodecContext *avctx, + void *data, int *got_sub_ptr, AVPacket *avpkt) +{ + AVSubtitle *sub = data; + MovTextContext *m = avctx->priv_data; + int ret, ts_start, ts_end; + AVBPrint buf; + char *ptr = avpkt->data; + char *end; + int text_length, tsmb_type, ret_tsmb; + uint64_t tsmb_size; + const uint8_t *tsmb; + + 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; + + ts_start = av_rescale_q(avpkt->pts, + avctx->time_base, + (AVRational){1,100}); + ts_end = av_rescale_q(avpkt->pts + avpkt->duration, + avctx->time_base, + (AVRational){1,100}); + + tsmb_size = 0; + m->tracksize = 2 + text_length; + m->style_entries = 0; + m->box_flags = 0; + m->count_s = 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) { + while (m->tracksize + 8 <= avpkt->size) { + // A box is a minimum of 8 bytes. + tsmb = ptr + m->tracksize - 2; + tsmb_size = AV_RB32(tsmb); + tsmb += 4; + tsmb_type = AV_RB32(tsmb); + tsmb += 4; + + if (tsmb_size == 1) { + if (m->tracksize + 16 > avpkt->size) + break; + tsmb_size = AV_RB64(tsmb); + tsmb += 8; + m->size_var = 16; + } else + m->size_var = 8; + //size_var is equal to 8 or 16 depending on the size of box + + if (m->tracksize + tsmb_size > avpkt->size) + break; + + for (size_t i = 0; i < box_count; i++) { + if (tsmb_type == box_types[i].type) { + if (m->tracksize + m->size_var + box_types[i].base_size > avpkt->size) + break; + ret_tsmb = box_types[i].decode(tsmb, m, avpkt); + if (ret_tsmb == -1) + break; + } + } + m->tracksize = m->tracksize + tsmb_size; + } + text_to_ass(&buf, ptr, end, m); + mov_text_cleanup(m); + } else + text_to_ass(&buf, ptr, end, m); + + ret = ff_ass_add_rect_bprint(sub, &buf, ts_start, ts_end - ts_start); + av_bprint_finalize(&buf, NULL); + if (ret < 0) + return ret; + *got_sub_ptr = sub->num_rects > 0; + return avpkt->size; +} + +AVCodec ff_movtext_decoder = { + .name = "mov_text", + .long_name = NULL_IF_CONFIG_SMALL("3GPP Timed Text subtitle"), + .type = AVMEDIA_TYPE_SUBTITLE, + .id = AV_CODEC_ID_MOV_TEXT, + .priv_data_size = sizeof(MovTextContext), + .init = mov_text_init, + .decode = mov_text_decode_frame, +}; |