On Tue, Apr 24, 2018 at 7:08 PM Aman Gupta <ffm...@tmm1.net> wrote: > From: Aman Gupta <a...@tmm1.net> > > Based largely on VLC's modules/codec/telx.c. > > Processes only teletext pages marked as subtitles, so depending > on the stream it might not produce any output. > > Subtitles are rendered directly to ASS, with support for background > colors and a best-effort at screen positioning.
This was meant to say foreground (text) colors. Background colors are not implemented. The ASS packets > are emitted in real time (similar to ccaption_dec's real_time > option), with -1 durations. The decoder expects that the player > will remove all existing subtitles whenever a new packet arrives. > > The teletext clear command is implemented using an empty subtitle, > which removes existing subtitles but does not render anything new. > --- > libavcodec/Makefile | 1 + > libavcodec/allcodecs.c | 1 + > libavcodec/teletextsubdec.c | 522 > ++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 524 insertions(+) > create mode 100644 libavcodec/teletextsubdec.c > > diff --git a/libavcodec/Makefile b/libavcodec/Makefile > index 4b8ad121db..83f2eab513 100644 > --- a/libavcodec/Makefile > +++ b/libavcodec/Makefile > @@ -593,6 +593,7 @@ OBJS-$(CONFIG_SVQ1_DECODER) += svq1dec.o > svq1.o svq13.o h263data.o > OBJS-$(CONFIG_SVQ1_ENCODER) += svq1enc.o svq1.o h263data.o \ > h263.o ituh263enc.o > OBJS-$(CONFIG_SVQ3_DECODER) += svq3.o svq13.o mpegutils.o > h264data.o > +OBJS-$(CONFIG_TELETEXTSUB_DECODER) += teletextsubdec.o ass.o > OBJS-$(CONFIG_TEXT_DECODER) += textdec.o ass.o > OBJS-$(CONFIG_TEXT_ENCODER) += srtenc.o ass_split.o > OBJS-$(CONFIG_TAK_DECODER) += takdec.o tak.o takdsp.o > diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c > index 4d4ef530e4..f0f23eccef 100644 > --- a/libavcodec/allcodecs.c > +++ b/libavcodec/allcodecs.c > @@ -634,6 +634,7 @@ extern AVCodec ff_subrip_encoder; > extern AVCodec ff_subrip_decoder; > extern AVCodec ff_subviewer_decoder; > extern AVCodec ff_subviewer1_decoder; > +extern AVCodec ff_teletextsub_decoder; > extern AVCodec ff_text_encoder; > extern AVCodec ff_text_decoder; > extern AVCodec ff_vplayer_decoder; > diff --git a/libavcodec/teletextsubdec.c b/libavcodec/teletextsubdec.c > new file mode 100644 > index 0000000000..f5f0f935ef > --- /dev/null > +++ b/libavcodec/teletextsubdec.c > @@ -0,0 +1,522 @@ > +/* > + * Minimal Teletext subtitle decoding for ffmpeg > + * Copyright (c) 2018 Aman Gupta > + * Copyright (c) 2013 Marton Balint > + * Copyright (c) 2005-2010, 2012 Wolfram Gloger > + * Copyright (c) 2007 Vincent Penne, VLC authors and VideoLAN > (modules/codec/telx.c) > + * Copyright (c) 2001-2005 dvb.matt, ProjectX java dvb decoder > + * > + * 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., 51 Franklin Street > <https://maps.google.com/?q=51+Franklin+Street&entry=gmail&source=g>, > Fifth Floor, Boston, MA 02110-1301 USA > + */ > + > +#include <stdbool.h> > +#include "avcodec.h" > +#include "libavcodec/ass.h" > +#include "libavcodec/dvbtxt.h" > +#include "libavutil/opt.h" > +#include "libavutil/bprint.h" > +#include "libavutil/internal.h" > +#include "libavutil/intreadwrite.h" > +#include "libavutil/log.h" > +#include "libavutil/reverse.h" > + > +#define NUM_ROWS 24 > +#define ROW_SIZE 40 > +#define NUM_MAGAZINES 9 > + > +typedef struct TeletextContext > +{ > + AVClass *class; > + int64_t pts; > + AVBPrint buffer; > + int readorder; > + > + uint8_t rows[NUM_ROWS][ROW_SIZE]; > + bool active[NUM_MAGAZINES]; > + int charset; > +} TeletextContext; > + > +/* > + * My doc only mentions 13 national characters, but experiments show there > + * are more, in france for example I already found two more (0x9 and 0xb). > + * > + * Conversion is in this order : > + * > + * 0x23 0x24 0x40 0x5b 0x5c 0x5d 0x5e 0x5f 0x60 0x7b 0x7c 0x7d 0x7e > + * (these are the standard ones) > + * 0x08 0x09 0x0a 0x0b 0x0c 0x0d (apparently a control character) 0x0e > 0x0f > + */ > +static const uint16_t national_charsets[][20] = { > + { 0x00a3, 0x0024, 0x0040, 0x00ab, 0x00bd, 0x00bb, 0x005e, 0x0023, > + 0x002d, 0x00bc, 0x00a6, 0x00be, 0x00f7 }, /* english ,000 */ > + > + { 0x00e9, 0x00ef, 0x00e0, 0x00eb, 0x00ea, 0x00f9, 0x00ee, 0x0023, > + 0x00e8, 0x00e2, 0x00f4, 0x00fb, 0x00e7, 0, 0x00eb, 0, 0x00ef }, /* > french ,001 */ > + > + { 0x0023, 0x00a4, 0x00c9, 0x00c4, 0x00d6, 0x00c5, 0x00dc, 0x005f, > + 0x00e9, 0x00e4, 0x00f6, 0x00e5, 0x00fc }, /* > swedish,finnish,hungarian ,010 */ > + > + { 0x0023, 0x016f, 0x010d, 0x0165, 0x017e, 0x00fd, 0x00ed, 0x0159, > + 0x00e9, 0x00e1, 0x011b, 0x00fa, 0x0161 }, /* czech,slovak ,011 */ > + > + { 0x0023, 0x0024, 0x00a7, 0x00c4, 0x00d6, 0x00dc, 0x005e, 0x005f, > + 0x00b0, 0x00e4, 0x00f6, 0x00fc, 0x00df }, /* german ,100 */ > + > + { 0x00e7, 0x0024, 0x00a1, 0x00e1, 0x00e9, 0x00ed, 0x00f3, 0x00fa, > + 0x00bf, 0x00fc, 0x00f1, 0x00e8, 0x00e0 }, /* portuguese,spanish > ,101 */ > + > + { 0x00a3, 0x0024, 0x00e9, 0x00b0, 0x00e7, 0x00bb, 0x005e, 0x0023, > + 0x00f9, 0x00e0, 0x00f2, 0x00e8, 0x00ec }, /* italian ,110 */ > + > + { 0x0023, 0x00a4, 0x0162, 0x00c2, 0x015e, 0x0102, 0x00ce, 0x0131, > + 0x0163, 0x00e2, 0x015f, 0x0103, 0x00ee }, /* rumanian ,111 */ > + > + /* I have these tables too, but I don't know how they can be > triggered */ > + { 0x0023, 0x0024, 0x0160, 0x0117, 0x0119, 0x017d, 0x010d, 0x016b, > + 0x0161, 0x0105, 0x0173, 0x017e, 0x012f }, /* lettish,lithuanian > ,1000 */ > + > + { 0x0023, 0x0144, 0x0105, 0x005a, 0x015a, 0x0141, 0x0107, 0x00f3, > + 0x0119, 0x017c, 0x015b, 0x0142, 0x017a }, /* polish, 1001 */ > + > + { 0x0023, 0x00cb, 0x010c, 0x0106, 0x017d, 0x0110, 0x0160, 0x00eb, > + 0x010d, 0x0107, 0x017e, 0x0111, 0x0161 }, /* > serbian,croatian,slovenian, 1010 */ > + > + { 0x0023, 0x00f5, 0x0160, 0x00c4, 0x00d6, 0x017e, 0x00dc, 0x00d5, > + 0x0161, 0x00e4, 0x00f6, 0x017e, 0x00fc }, /* estonian ,1011 */ > + > + { 0x0054, 0x011f, 0x0130, 0x015e, 0x00d6, 0x00c7, 0x00dc, 0x011e, > + 0x0131, 0x015f, 0x00f6, 0x00e7, 0x00fc }, /* turkish ,1100 */ > +}; > + > +static const char *color_mappings[8] = { > + "{\\c&H000000&}", // black > + "{\\c&H0000FF&}", // red > + "{\\c&H00FF00&}", // green > + "{\\c&H00FFFF&}", // yellow > + "{\\c&HFF0000&}", // blue > + "{\\c&HFF00FF&}", // magenta > + "{\\c&HFFFF00&}", // cyan > + "{\\c&HFFFFFF&}" // white > +}; > + > +static int hamming(int a) > +{ > + switch (a) { > + case 0xA8: return 0; > + case 0x0B: return 1; > + case 0x26: return 2; > + case 0x85: return 3; > + case 0x92: return 4; > + case 0x31: return 5; > + case 0x1C: return 6; > + case 0xBF: return 7; > + case 0x40: return 8; > + case 0xE3: return 9; > + case 0xCE: return 10; > + case 0x6D: return 11; > + case 0x7A: return 12; > + case 0xD9: return 13; > + case 0xF4: return 14; > + case 0x57: return 15; > + default: return -1; // decoding error , not yet corrected > + } > +} > + > +// ucs-2 --> utf-8 > +// this is not a general function, but it's enough for what we do here > +// the result buffer need to be at least 4 bytes long > +static void to_utf8(char *res, uint16_t ch) > +{ > + if (ch >= 0x80) { > + if (ch >= 0x800) { > + res[0] = (ch >> 12) | 0xE0; > + res[1] = ((ch >> 6) & 0x3F) | 0x80; > + res[2] = (ch & 0x3F) | 0x80; > + res[3] = 0; > + } else { > + res[0] = (ch >> 6) | 0xC0; > + res[1] = (ch & 0x3F) | 0x80; > + res[2] = 0; > + } > + } else { > + res[0] = ch; > + res[1] = 0; > + } > +} > + > +static void decode_string(AVCodecContext *avctx, AVBPrint *buf, > + const uint8_t *packet, int *leading, int *olen) > +{ > + TeletextContext *ctx = avctx->priv_data; > + int i, len = 0; > + int end_box = 0; > + bool char_seen = false; > + char utf8[7]; > + const uint16_t *charset = national_charsets[ctx->charset]; > + av_bprint_clear(buf); > + *leading = 0; > + > + for (i = 0; i < ROW_SIZE; i++) { > + int in = ff_reverse[packet[i]] & 0x7f; > + uint16_t out = 32; > + > + switch (in) { > + /* special national characters */ > + case 0x23: out = charset[0]; break; > + case 0x24: out = charset[1]; break; > + case 0x40: out = charset[2]; break; > + case 0x5b: out = charset[3]; break; > + case 0x5c: out = charset[4]; break; > + case 0x5d: out = charset[5]; break; > + case 0x5e: out = charset[6]; break; > + case 0x5f: out = charset[7]; break; > + case 0x60: out = charset[8]; break; > + case 0x7b: out = charset[9]; break; > + case 0x7c: out = charset[10]; break; > + case 0x7d: out = charset[11]; break; > + case 0x7e: out = charset[12]; break; > + > + /* control codes */ > + case 0xd: > + i++; > + in = ff_reverse[packet[i]] & 0x7f; > + if (in == 0xb) > + in = 7; > + if (in >= 0 && in < 8) { > + av_bprintf(buf, "%s", color_mappings[in]); > + } > + continue; > + > + case 0xa: > + end_box++; > + if (end_box == 1) > + continue; > + break; > + > + case 0xb: > + continue; > + > + /* color codes */ > + case 0x0: > + case 0x1: > + case 0x2: > + case 0x3: > + case 0x4: > + case 0x5: > + case 0x6: > + case 0x7: > + av_bprintf(buf, "%s", color_mappings[in]); > + break; > + > + default: > + /* non documented national range 0x08 - 0x0f */ > + if (in >= 0x08 && in <= 0x0f) { > + out = charset[13 + in - 8]; > + break; > + } > + > + /* normal ascii */ > + if (in >= 32 && in < 0x7f) > + out = in; > + } > + > + if (end_box == 2) > + break; > + > + /* handle undefined national characters */ > + if (out == 0) > + out = 32; > + > + if (out == 32 && !char_seen) > + (*leading)++; > + else if (out != 32) > + char_seen = true; > + > + /* convert to utf-8 */ > + to_utf8(utf8, out); > + av_bprintf(buf, "%s", utf8); > + > + if (char_seen || out != 32) > + len += strlen(utf8); > + } > + > + /* remove trailing spaces */ > + for (i = buf->len-1; i >= 0 && buf->str[i] == 32; i--) > + ; > + buf->str[i+1] = 0; > + buf->len = i; > + > + *olen = len; > +} > + > +static int teletext_init_decoder(AVCodecContext *avctx) > +{ > + TeletextContext *ctx = avctx->priv_data; > + av_bprint_init(&ctx->buffer, 0, AV_BPRINT_SIZE_UNLIMITED); > + ctx->pts = AV_NOPTS_VALUE; > + return ff_ass_subtitle_header(avctx, > + "Monospace", > + ASS_DEFAULT_FONT_SIZE, > + ASS_DEFAULT_COLOR, > + ASS_DEFAULT_BACK_COLOR, > + ASS_DEFAULT_BOLD, > + ASS_DEFAULT_ITALIC, > + ASS_DEFAULT_UNDERLINE, > + 3, > + ASS_DEFAULT_ALIGNMENT); > +} > + > +static int teletext_close_decoder(AVCodecContext *avctx) > +{ > + TeletextContext *ctx = avctx->priv_data; > + ctx->pts = AV_NOPTS_VALUE; > + av_bprint_finalize(&ctx->buffer, NULL); > + return 0; > +} > + > +static void teletext_flush(AVCodecContext *avctx) > +{ > + TeletextContext *ctx = avctx->priv_data; > + int i; > + ctx->pts = AV_NOPTS_VALUE; > + if (!(avctx->flags2 & AV_CODEC_FLAG2_RO_FLUSH_NOOP)) > + ctx->readorder = 0; > + for (i = 0; i < NUM_ROWS; i++) > + ctx->rows[i][0] = 0; > + av_bprint_clear(&ctx->buffer); > +} > + > +static int capture_screen(AVCodecContext *avctx) > +{ > + TeletextContext *ctx = avctx->priv_data; > + int i, j; > + int tab = 0; > + int num_rows = 0; > + bool align_center = false, align_right = false; > + bool maybe_center = false; > + char prev_line[128] = {0}; > + AVBPrint line; > + av_bprint_init(&line, 0, AV_BPRINT_SIZE_UNLIMITED); > + av_bprint_clear(&ctx->buffer); > + > + for (i = 0; i < NUM_ROWS; i++) { > + int leading, len; > + int spaces = 0; > + const uint8_t *row = ctx->rows[i]; > + if (row[0] == 0) > + continue; > + num_rows++; > + > + av_bprint_clear(&line); > + decode_string(avctx, &line, row, &leading, &len); > + > + // av_log(avctx, AV_LOG_DEBUG, "line[%d]: '%s' [leading=%d, > len=%d]\n", > + // i, line.str, leading, len); > + > + for (j = 0; j < line.len; j++) { > + if (line.str[j] == ' ') > + spaces++; > + else > + break; > + } > + > + if (!tab || spaces < tab) > + tab = spaces; > + > + if (leading > 0 && leading + len > 35) > + align_right = true; > + else if (leading > 0 && leading*2 + len <= 36) > + align_center = true; > + else if (leading == 0 && len == 34) > + maybe_center = true; > + } > + > + if (num_rows == 1 && maybe_center) > + align_center = true; > + > + for (i = 0; i < NUM_ROWS; i++) { > + int leading, len; > + int x, y, alignment = 7; > + const uint8_t *row = ctx->rows[i]; > + bool char_seen = false; > + if (row[0] == 0) > + continue; > + > + av_bprint_clear(&line); > + decode_string(avctx, &line, row, &leading, &len); > + > + len = FFMIN(sizeof(prev_line), line.len+1); > + if (strncmp(prev_line, line.str, len) == 0) > + continue; > + strncpy(prev_line, line.str, len); > + > + /* skip leading space */ > + j = 0; > + while (line.str[j] == ' ' && j < tab) > + j++; > + > + x = ASS_DEFAULT_PLAYRESX * (0.1 + (0.80 / 34) * j); > + y = ASS_DEFAULT_PLAYRESY * (0.1 + (0.80 / 25) * i); > + > + if (align_center) { > + x = ASS_DEFAULT_PLAYRESX * 0.5; > + alignment = 8; > + } else if (align_right) { > + x = ASS_DEFAULT_PLAYRESX * 0.9; > + alignment = 9; > + } > + > + av_bprintf(&ctx->buffer, "{\\an%d}{\\pos(%d,%d)}", alignment, x, > y); > + for (; j <= line.len; j++) { > + if (line.str[j] == 32 && !char_seen && !align_center && > !align_right) > + av_bprintf(&ctx->buffer, "\\h"); > + else { > + av_bprintf(&ctx->buffer, "%c", line.str[j]); > + char_seen = true; > + } > + } > + av_bprintf(&ctx->buffer, "\\N"); > + } > + > + av_bprint_finalize(&line, NULL); > + if (!av_bprint_is_complete(&ctx->buffer)) > + return AVERROR(ENOMEM); > + return 0; > +} > + > +static int teletext_decode_frame(AVCodecContext *avctx, void *data, int > *got_sub, AVPacket *pkt) > +{ > + TeletextContext *ctx = avctx->priv_data; > + AVSubtitle *sub = data; > + int ret = 0; > + int offset = 0; > + bool updated = false, erased = false; > + > + if (avctx->pkt_timebase.num && pkt->pts != AV_NOPTS_VALUE) > + ctx->pts = av_rescale_q(pkt->pts, avctx->pkt_timebase, > AV_TIME_BASE_Q); > + > + if (pkt->size) { > + const int full_pes_size = pkt->size + 45; /* PES header is 45 > bytes */ > + > + // We allow unreasonably big packets, even if the standard only > allows a max size of 1472 > + if (full_pes_size < 184 || full_pes_size > 65504 || full_pes_size > % 184 != 0) > + return AVERROR_INVALIDDATA; > + > + if (!ff_data_identifier_is_teletext(*pkt->data)) > + return pkt->size; > + > + for (offset = 1; offset + 46 <= pkt->size; offset += 46) { > + int mpag, row, magazine; > + uint8_t *packet = pkt->data + offset; > + if (packet[0] == 0xFF) > + continue; > + > + mpag = (hamming(packet[4]) << 4) | hamming(packet[5]); > + if (mpag < 0) > + continue; > + > + row = 0xFF & ff_reverse[mpag]; > + magazine = 7 & row; > + if (magazine == 0) > + magazine = 8; > + row >>= 3; > + > + if (row == 0) { // row 0: flags and header line > + int flag = 0; > + int i, page, f_charset; > + bool f_erase, f_subtitle, f_inhibit, f_suppress, > f_update, f_news; > + > + for (i = 0; i < 6; i++) > + flag |= (0xF & (ff_reverse[hamming(packet[8+i])] >> > 4)) << (4*i); > + > + page = (0xF0 & ff_reverse[hamming(packet[7])] ) | > + (0x0F & (ff_reverse[hamming(packet[6])] >> 4)); > + > + f_erase = 1 & (flag>>7); > + f_news = 1 & (flag>>15); > + f_subtitle = 1 & (flag>>15); > + f_suppress = 1 & (flag>>16); > + f_update = 1 & (flag>>17); > + f_inhibit = 1 & (flag>>19); > + f_charset = 7 & (flag>>21); > + > + ctx->active[magazine] = f_subtitle; > + if (!ctx->active[magazine]) > + continue; > + > + ctx->charset = f_charset; > + > + // av_log(avctx, AV_LOG_DEBUG, "magazine=%d page=%d > erase=%d subtitle=%d news=%d charset=%d inhibit=%d suppress=%d update=%d\n", > + // magazine, page, f_erase, f_subtitle, f_news, > f_charset, f_inhibit, f_suppress, f_update); > + > + if (f_erase) { > + for (i = 0; i < NUM_ROWS; i++) > + ctx->rows[i][0] = 0; > + erased = true; > + continue; > + } > + > + } else if (row < 24) { // row 1-23: normal lines > + if (!ctx->active[magazine]) > + continue; > + if (memcmp(ctx->rows[row], packet+6, ROW_SIZE) != 0) { > + updated |= true; > + memcpy(ctx->rows[row], packet+6, ROW_SIZE); > + } > + > + // int j; > + // av_log(avctx, AV_LOG_DEBUG, "row[%d]: ", row); > + // for (j = 0; j < ROW_SIZE; j++) { > + // int in = ff_reverse[ctx->rows[row][j]] & 0x7f; > + // av_log(avctx, AV_LOG_DEBUG, "0x%x ", in); > + // } > + // av_log(avctx, AV_LOG_DEBUG, "\n"); > + } > + } > + } > + > + if (updated || (erased && ctx->buffer.len)) { > + ret = capture_screen(avctx); > + if (ret < 0) > + return ret; > + ret = ff_ass_add_rect(sub, ctx->buffer.str, ctx->readorder++, 0, > NULL, NULL); > + if (ret < 0) > + return ret; > + sub->end_display_time = -1; > + } > + > + *got_sub = sub->num_rects > 0; > + return offset; > +} > + > +static const AVClass teletext_class = { > + .class_name = "teletextsub", > + .item_name = av_default_item_name, > + .version = LIBAVUTIL_VERSION_INT, > +}; > + > +AVCodec ff_teletextsub_decoder = { > + .name = "teletext_subtitle", > + .long_name = NULL_IF_CONFIG_SMALL("Minimal DVB teletext subtitle > decoder"), > + .type = AVMEDIA_TYPE_SUBTITLE, > + .id = AV_CODEC_ID_DVB_TELETEXT, > + .priv_data_size = sizeof(TeletextContext), > + .init = teletext_init_decoder, > + .close = teletext_close_decoder, > + .decode = teletext_decode_frame, > + .capabilities = AV_CODEC_CAP_DELAY, > + .flush = teletext_flush, > + .priv_class= &teletext_class, > +}; > -- > 2.14.2 > > _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
