gstreamer/subprojects/gst-plugins-base/gst/subparse/qttextparse.c

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/* GStreamer QTtext subtitle parser
* Copyright (c) 2009 Thiago Santos <thiago.sousa.santos collabora co uk>>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
/* References:
* http://www.apple.com/quicktime/tutorials/texttracks.html
* http://www.apple.com/quicktime/tutorials/textdescriptors.html
*/
#include "qttextparse.h"
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#define MIN_TO_NSEC (60 * GST_SECOND)
#define HOUR_TO_NSEC (60 * MIN_TO_NSEC)
#define GST_QTTEXT_CONTEXT(state) ((GstQTTextContext *) (state)->user_data)
typedef struct _GstQTTextContext GstQTTextContext;
struct _GstQTTextContext
{
/* timing variables */
gint timescale;
gboolean absolute;
guint64 start_time;
gboolean markup_open;
gboolean need_markup;
gchar *font;
gint font_size;
gchar *bg_color;
gchar *fg_color;
gboolean bold;
gboolean italic;
};
void
qttext_context_init (ParserState * state)
{
GstQTTextContext *context;
state->user_data = g_new0 (GstQTTextContext, 1);
context = GST_QTTEXT_CONTEXT (state);
/* we use 1000 as a default */
context->timescale = 1000;
context->absolute = TRUE;
context->markup_open = FALSE;
context->need_markup = FALSE;
context->font_size = 12;
}
void
qttext_context_deinit (ParserState * state)
{
if (state->user_data != NULL) {
GstQTTextContext *context = GST_QTTEXT_CONTEXT (state);
g_free (context->font);
g_free (context->bg_color);
g_free (context->fg_color);
g_free (state->user_data);
state->user_data = NULL;
}
}
/*
* Reads the string right after the ':'
*/
static gchar *
read_str (const gchar * line, const gchar * end)
{
gint index = 0;
while (line[index] != ':' && line[index] != '}') {
index++;
}
if (line[index] != ':')
return NULL;
index++;
while (line[index] == ' ')
index++;
return g_strndup (line + index, (end - (line + index)));
}
/* search for the ':' and parse the number right after it */
static gint
read_int (const gchar * line)
{
gint index = 0;
while (line[index] != ':' && line[index] != '}') {
index++;
}
if (line[index] != ':')
return 0;
index++;
return atoi (line + index);
}
/* skip the ':' and then match the following string
* with 'match', but only if it before 'upto' */
static gboolean
string_match (const gchar * line, const gchar * match, const gchar * upto)
{
gchar *result = strstr (line, match);
return (result < upto);
}
/*
* Reads the color values and stores them in r, g and b.
*/
static gboolean
read_color (const gchar * line, gint * r, gint * g, gint * b)
{
gint index = 0;
while (line[index] != ':' && line[index] != '}') {
index++;
}
if (line[index] != ':')
return FALSE;
index++;
*r = atoi (line + index);
while (line[index] != '}' && line[index] != ',') {
index++;
}
if (line[index] != ',')
return FALSE;
index++;
*g = atoi (line + index);
while (line[index] != '}' && line[index] != ',') {
index++;
}
if (line[index] != ',')
return FALSE;
index++;
*b = atoi (line + index);
return TRUE;
}
static gchar *
make_color (gint r, gint g, gint b)
{
/* qttext goes up to 65535, while pango goes to 255 */
r /= 256;
g /= 256;
b /= 256;
return g_strdup_printf ("#%02X%02X%02X", r, g, b);
}
static gboolean
qttext_parse_tag (ParserState * state, const gchar * line, gint * index)
{
gchar *next;
gint next_index;
gint aux;
gchar *str;
gint r, g, b;
GstQTTextContext *context = GST_QTTEXT_CONTEXT (state);
g_assert (line[*index] == '{');
next = strchr (line + *index, '}');
if (next == NULL) {
goto error_out;
} else {
next_index = 1 + (next - line);
}
g_assert (line[next_index - 1] == '}');
*index = *index + 1; /* skip the { */
/* now identify our tag */
/* FIXME: those should be case unsensitive */
/* TODO: there are other tags that could be added here */
if (strncmp (line + *index, "QTtext", 6) == 0) {
/* NOP */
} else if (strncmp (line + *index, "font", 4) == 0) {
str = read_str (line + *index + 4, line + next_index - 1);
if (str) {
g_free (context->font);
context->font = str;
context->need_markup = TRUE;
GST_DEBUG ("Setting qttext font to %s", str);
} else {
GST_WARNING ("Failed to parse qttext font at line: %s", line);
}
} else if (strncmp (line + *index, "size", 4) == 0) {
aux = read_int (line + *index + 4);
if (aux == 0) {
GST_WARNING ("Invalid size at line %s, using 12", line);
context->font_size = 12;
} else {
GST_DEBUG ("Setting qttext font-size to: %d", aux);
context->font_size = aux;
}
context->need_markup = TRUE;
} else if (strncmp (line + *index, "textColor", 9) == 0) {
if (read_color (line + *index + 9, &r, &g, &b)) {
context->fg_color = make_color (r, g, b);
GST_DEBUG ("Setting qttext fg color to %s", context->fg_color);
} else {
GST_WARNING ("Failed to read textColor at line %s", line);
}
context->need_markup = TRUE;
} else if (strncmp (line + *index, "backColor", 9) == 0) {
if (read_color (line + *index + 9, &r, &g, &b)) {
context->bg_color = make_color (r, g, b);
GST_DEBUG ("Setting qttext bg color to %s", context->bg_color);
} else {
GST_WARNING ("Failed to read backColor at line %s, disabling", line);
g_free (context->bg_color);
context->bg_color = NULL;
}
context->need_markup = TRUE;
} else if (strncmp (line + *index, "plain", 5) == 0) {
context->bold = FALSE;
context->italic = FALSE;
context->need_markup = TRUE;
GST_DEBUG ("Setting qttext style to plain");
} else if (strncmp (line + *index, "bold", 4) == 0) {
context->bold = TRUE;
context->italic = FALSE;
context->need_markup = TRUE;
GST_DEBUG ("Setting qttext style to bold");
} else if (strncmp (line + *index, "italic", 6) == 0) {
context->bold = FALSE;
context->italic = TRUE;
context->need_markup = TRUE;
GST_DEBUG ("Setting qttext style to italic");
} else if (strncmp (line + *index, "timescale", 9) == 0) {
aux = read_int (line + *index + 9);
if (aux == 0) {
GST_WARNING ("Couldn't interpret timescale at line %s, using 1000", line);
context->timescale = 1000;
} else {
GST_DEBUG ("Setting qttext timescale to: %d", aux);
context->timescale = aux;
}
} else if (strncmp (line + *index, "timestamps", 10) == 0) {
if (string_match (line + *index + 10, "relative", line + next_index)) {
GST_DEBUG ("Setting qttext timestamps to relative");
context->absolute = FALSE;
} else {
/* call it absolute otherwise */
GST_DEBUG ("Setting qttext timestamps to absolute");
context->absolute = TRUE;
}
} else {
GST_WARNING ("Unused qttext tag starting at: %s", line + *index);
}
*index = next_index;
return TRUE;
error_out:
{
GST_WARNING ("Failed to parse qttext tag at line %s", line);
return FALSE;
}
}
static guint64
qttext_parse_timestamp (ParserState * state, const gchar * line, gint index)
{
int ret;
gint hour, min, sec, dec;
GstQTTextContext *context = GST_QTTEXT_CONTEXT (state);
ret = sscanf (line + index, "[%d:%d:%d.%d]", &hour, &min, &sec, &dec);
if (ret != 3 && ret != 4) {
/* bad timestamp */
GST_WARNING ("Bad qttext timestamp found: %s", line);
return 0;
}
if (ret == 3) {
/* be forgiving for missing decimal part */
dec = 0;
}
/* parse the decimal part according to the timescale */
g_assert (context->timescale != 0);
dec = (GST_SECOND * dec) / context->timescale;
/* return the result */
return hour * HOUR_TO_NSEC + min * MIN_TO_NSEC + sec * GST_SECOND + dec;
}
static void
qttext_open_markup (ParserState * state)
{
GstQTTextContext *context = GST_QTTEXT_CONTEXT (state);
g_string_append (state->buf, "<span");
/* add your markup tags here */
if (context->font)
g_string_append_printf (state->buf, " font='%s %d'", context->font,
context->font_size);
else
g_string_append_printf (state->buf, " font='%d'", context->font_size);
if (context->bg_color)
g_string_append_printf (state->buf, " bgcolor='%s'", context->bg_color);
if (context->fg_color)
g_string_append_printf (state->buf, " color='%s'", context->fg_color);
if (context->bold)
g_string_append (state->buf, " weight='bold'");
if (context->italic)
g_string_append (state->buf, " style='italic'");
g_string_append (state->buf, ">");
}
static void
qttext_prepare_text (ParserState * state)
{
GstQTTextContext *context = GST_QTTEXT_CONTEXT (state);
if (state->buf == NULL) {
state->buf = g_string_sized_new (256); /* this should be enough */
} else {
g_string_append (state->buf, "\n");
}
/* if needed, add pango markup */
if (context->need_markup) {
if (context->markup_open) {
g_string_append (state->buf, "</span>");
}
qttext_open_markup (state);
context->markup_open = TRUE;
}
}
static void
qttext_parse_text (ParserState * state, const gchar * line, gint index)
{
qttext_prepare_text (state);
g_string_append (state->buf, line + index);
}
static gchar *
qttext_get_text (ParserState * state)
{
gchar *ret;
GstQTTextContext *context = GST_QTTEXT_CONTEXT (state);
if (state->buf == NULL)
return NULL;
if (context->markup_open) {
g_string_append (state->buf, "</span>");
}
ret = g_string_free (state->buf, FALSE);
state->buf = NULL;
context->markup_open = FALSE;
return ret;
}
gchar *
parse_qttext (ParserState * state, const gchar * line)
{
gint i;
guint64 ts;
gchar *ret = NULL;
GstQTTextContext *context = GST_QTTEXT_CONTEXT (state);
i = 0;
while (line[i] != '\0') {
/* find first interesting character from 'i' onwards */
if (line[i] == '{') {
/* this is a tag, parse it */
if (!qttext_parse_tag (state, line, &i)) {
break;
}
} else if (line[i] == '[') {
/* this is a time, convert it to a timestamp */
ts = qttext_parse_timestamp (state, line, i);
/* check if we have pending text to send, in case we prepare it */
if (state->buf) {
ret = qttext_get_text (state);
if (context->absolute)
state->duration = ts - context->start_time;
else
state->duration = ts;
state->start_time = context->start_time;
}
state->buf = NULL;
if (ts == 0) {
/* this is an error */
} else {
if (context->absolute)
context->start_time = ts;
else
context->start_time += ts;
}
/* we assume there is nothing else on this line */
break;
} else if (line[i] == ' ' || line[i] == '\t') {
i++; /* NOP */
} else {
/* this is the actual text, output the rest of the line as it */
qttext_parse_text (state, line, i);
break;
}
}
return ret;
}