gstreamer/gst/subparse/gstssaparse.c

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/* GStreamer SSA subtitle parser
* Copyright (c) 2006 Tim-Philipp Müller <tim centricular net>
*
* 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., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/* Super-primitive SSA parser - we just want the text and ignore
* everything else like styles and timing codes etc. for now */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <string.h>
#include "gstssaparse.h"
GST_DEBUG_CATEGORY_STATIC (ssa_parse_debug);
#define GST_CAT_DEFAULT ssa_parse_debug
static GstStaticPadTemplate sink_templ = GST_STATIC_PAD_TEMPLATE ("sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("application/x-ssa; application/x-ass")
);
static GstStaticPadTemplate src_templ = GST_STATIC_PAD_TEMPLATE ("src",
GST_PAD_SRC,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("text/x-pango-markup")
);
GST_BOILERPLATE (GstSsaParse, gst_ssa_parse, GstElement, GST_TYPE_ELEMENT)
static GstStateChangeReturn gst_ssa_parse_change_state (GstElement *
element, GstStateChange transition);
static gboolean gst_ssa_parse_setcaps (GstPad * sinkpad, GstCaps * caps);
static gboolean gst_ssa_parse_src_event (GstPad * pad, GstEvent * event);
static gboolean gst_ssa_parse_sink_event (GstPad * pad, GstEvent * event);
static GstFlowReturn gst_ssa_parse_chain (GstPad * sinkpad,
GstBuffer * buf);
static void gst_ssa_parse_base_init (gpointer klass)
{
GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
static GstElementDetails ssa_parse_details = {
"SSA Subtitle Parser",
"Codec/Parser/Subtitle",
"Parses SSA subtitle streams",
"Tim-Philipp Müller <tim centricular net>"
};
gst_element_class_add_pad_template (element_class,
gst_static_pad_template_get (&sink_templ));
gst_element_class_add_pad_template (element_class,
gst_static_pad_template_get (&src_templ));
gst_element_class_set_details (element_class, &ssa_parse_details);
GST_DEBUG_CATEGORY_INIT (ssa_parse_debug, "ssaparse", 0,
"SSA subtitle parser");
}
static void
gst_ssa_parse_dispose (GObject * object)
{
GstSsaParse *parse = GST_SSA_PARSE (object);
g_free (parse->ini);
parse->ini = NULL;
GST_CALL_PARENT (G_OBJECT_CLASS, dispose, (object));
}
static void
gst_ssa_parse_init (GstSsaParse * parse, GstSsaParseClass * klass)
{
parse->sinkpad = gst_pad_new_from_static_template (&sink_templ, "sink");
gst_pad_set_setcaps_function (parse->sinkpad,
GST_DEBUG_FUNCPTR (gst_ssa_parse_setcaps));
gst_pad_set_chain_function (parse->sinkpad,
GST_DEBUG_FUNCPTR (gst_ssa_parse_chain));
gst_pad_set_event_function (parse->sinkpad,
GST_DEBUG_FUNCPTR (gst_ssa_parse_sink_event));
gst_element_add_pad (GST_ELEMENT (parse), parse->sinkpad);
parse->srcpad = gst_pad_new_from_static_template (&src_templ, "src");
gst_pad_set_event_function (parse->srcpad,
GST_DEBUG_FUNCPTR (gst_ssa_parse_src_event));
gst_element_add_pad (GST_ELEMENT (parse), parse->srcpad);
gst_pad_use_fixed_caps (parse->srcpad);
gst_pad_set_caps (parse->srcpad,
gst_static_pad_template_get_caps (&src_templ));
parse->ini = NULL;
parse->framed = FALSE;
}
static void
gst_ssa_parse_class_init (GstSsaParseClass * klass)
{
GObjectClass *object_class = G_OBJECT_CLASS (klass);
GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
object_class->dispose = GST_DEBUG_FUNCPTR (gst_ssa_parse_dispose);
element_class->change_state = GST_DEBUG_FUNCPTR (gst_ssa_parse_change_state);
}
static gboolean
gst_ssa_parse_src_event (GstPad * pad, GstEvent * event)
{
return gst_pad_event_default (pad, event);
}
static gboolean
gst_ssa_parse_sink_event (GstPad * pad, GstEvent * event)
{
return gst_pad_event_default (pad, event);
}
static gboolean
gst_ssa_parse_setcaps (GstPad * sinkpad, GstCaps * caps)
{
GstSsaParse *parse = GST_SSA_PARSE (GST_PAD_PARENT (sinkpad));
const GValue *val;
GstStructure *s;
const gchar bom_utf8[] = { 0xEF, 0xBB, 0xBF };
GstBuffer *priv;
gchar *data;
guint size;
s = gst_caps_get_structure (caps, 0);
val = gst_structure_get_value (s, "codec_data");
if (val == NULL) {
parse->framed = FALSE;
GST_ERROR ("Only SSA subtitles embedded in containers are supported");
return FALSE;
}
parse->framed = TRUE;
priv = (GstBuffer *) gst_value_get_mini_object (val);
g_return_val_if_fail (priv != NULL, FALSE);
gst_buffer_ref (priv);
data = (gchar *) GST_BUFFER_DATA (priv);
size = GST_BUFFER_SIZE (priv);
/* skip UTF-8 BOM */
if (size >= 3 && memcmp (data, bom_utf8, 3) == 0) {
data += 3;
size -= 3;
}
if (!strstr (data, "[Script Info]")) {
GST_WARNING_OBJECT (parse, "Invalid Init section - no Script Info header");
gst_buffer_unref (priv);
return FALSE;
}
if (!g_utf8_validate (data, size, NULL)) {
GST_WARNING_OBJECT (parse, "Init section is not valid UTF-8");
gst_buffer_unref (priv);
return FALSE;
}
/* FIXME: parse initial section */
parse->ini = g_strndup (data, size);
GST_LOG_OBJECT (parse, "Init section:\n%s", parse->ini);
gst_buffer_unref (priv);
return TRUE;
}
static gboolean
gst_ssa_parse_remove_override_codes (GstSsaParse * parse, gchar * txt)
{
gchar *t, *end;
gboolean removed_any = FALSE;
while ((t = strchr (txt, '{'))) {
end = strchr (txt, '}');
if (end == NULL) {
GST_WARNING_OBJECT (parse, "Missing { for style override code");
return removed_any;
}
/* move terminating NUL character forward as well */
g_memmove (t, end + 1, strlen (end + 1) + 1);
removed_any = TRUE;
}
return removed_any;
}
static GstFlowReturn
gst_ssa_parse_parse_line (GstSsaParse * parse, gchar * txt,
GstClockTime start, GstClockTime duration)
{
GstFlowReturn ret;
GstBuffer *buf;
gchar *t, *escaped;
gint num, i, len;
num = atoi (txt);
GST_LOG_OBJECT (parse, "Parsing line #%d at %" GST_TIME_FORMAT,
num, GST_TIME_ARGS (start));
/* skip all non-text fields before the actual text */
t = txt;
for (i = 0; i < 8; ++i) {
t = strchr (t, ',');
if (t == NULL)
return GST_FLOW_ERROR;
++t;
}
GST_LOG_OBJECT (parse, "Text : %s", t);
if (gst_ssa_parse_remove_override_codes (parse, t)) {
GST_LOG_OBJECT (parse, "Clean: %s", t);
}
/* we claim to output pango markup, so we must escape the
* text even if we don't actually use any pango markup yet */
escaped = g_markup_printf_escaped ("%s", t);
len = strlen (escaped);
buf = gst_buffer_new_and_alloc (len + 1);
memcpy (GST_BUFFER_DATA (buf), escaped, len + 1); /* incl. terminating NUL */
g_free (escaped);
GST_BUFFER_TIMESTAMP (buf) = start;
GST_BUFFER_DURATION (buf) = duration;
gst_buffer_set_caps (buf, GST_PAD_CAPS (parse->srcpad));
GST_LOG_OBJECT (parse, "Pushing buffer with timestamp %" GST_TIME_FORMAT
" and duration %" GST_TIME_FORMAT, GST_TIME_ARGS (start),
GST_TIME_ARGS (duration));
ret = gst_pad_push (parse->srcpad, buf);
if (ret != GST_FLOW_OK) {
GST_DEBUG_OBJECT (parse, "Push returned flow %s", gst_flow_get_name (ret));
}
return ret;
}
static GstFlowReturn
gst_ssa_parse_chain (GstPad * sinkpad, GstBuffer * buf)
{
GstFlowReturn ret;
GstSsaParse *parse = GST_SSA_PARSE (GST_PAD_PARENT (sinkpad));
GstClockTime ts;
gchar *txt;
/* make double-sure it's 0-terminated and all */
txt = g_strndup ((gchar *) GST_BUFFER_DATA (buf), GST_BUFFER_SIZE (buf));
if (txt == NULL)
return GST_FLOW_UNEXPECTED;
ts = GST_BUFFER_TIMESTAMP (buf);
ret = gst_ssa_parse_parse_line (parse, txt, ts, GST_BUFFER_DURATION (buf));
if (ret != GST_FLOW_OK) {
GST_WARNING_OBJECT (parse, "Failed to parse dialog line '%s'", txt);
if (GST_CLOCK_TIME_IS_VALID (ts)) {
/* just advance time without sending anything */
gst_pad_push_event (parse->srcpad,
gst_event_new_new_segment (TRUE, 1.0, GST_FORMAT_TIME, ts, -1, ts));
ret = GST_FLOW_OK;
}
}
g_free (txt);
return ret;
}
static GstStateChangeReturn
gst_ssa_parse_change_state (GstElement * element, GstStateChange transition)
{
GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;
GstSsaParse *parse = GST_SSA_PARSE (element);
switch (transition) {
case GST_STATE_CHANGE_READY_TO_PAUSED:
break;
default:
break;
}
ret = parent_class->change_state (element, transition);
if (ret == GST_STATE_CHANGE_FAILURE)
return ret;
switch (transition) {
case GST_STATE_CHANGE_PAUSED_TO_READY:
g_free (parse->ini);
parse->ini = NULL;
parse->framed = FALSE;
break;
default:
break;
}
return ret;
}