blob: 4a3a7e75be397d937bdcc69337d192d8079bf8e5 [file] [log] [blame]
/* GStreamer CDXA sync strippper / VCD parser
* Copyright (C) 2004 Ronald Bultje <rbultje@ronald.bitfreak.net>
* Copyright (C) 2008 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., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <string.h>
#include "gstvcdparse.h"
GST_DEBUG_CATEGORY_EXTERN (vcdparse_debug);
#define GST_CAT_DEFAULT vcdparse_debug
static gboolean gst_vcd_parse_sink_event (GstPad * pad, GstEvent * event);
static gboolean gst_vcd_parse_src_event (GstPad * pad, GstEvent * event);
static gboolean gst_vcd_parse_src_query (GstPad * pad, GstQuery * query);
static GstFlowReturn gst_vcd_parse_chain (GstPad * pad, GstBuffer * buf);
static GstStateChangeReturn gst_vcd_parse_change_state (GstElement * element,
GstStateChange transition);
static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
GST_PAD_SINK,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("video/x-vcd")
);
static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
GST_PAD_SRC,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("video/mpeg, systemstream = (boolean) TRUE")
);
GST_BOILERPLATE (GstVcdParse, gst_vcd_parse, GstElement, GST_TYPE_ELEMENT);
static void
gst_vcd_parse_base_init (gpointer klass)
{
GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
gst_element_class_add_pad_template (element_class,
gst_static_pad_template_get (&sink_factory));
gst_element_class_add_pad_template (element_class,
gst_static_pad_template_get (&src_factory));
gst_element_class_set_static_metadata (element_class, "(S)VCD stream parser",
"Codec/Parser", "Strip (S)VCD stream from its sync headers",
"Tim-Philipp Müller <tim centricular net>, "
"Ronald Bultje <rbultje@ronald.bitfreak.net>");
}
static void
gst_vcd_parse_class_init (GstVcdParseClass * klass)
{
GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
element_class->change_state = GST_DEBUG_FUNCPTR (gst_vcd_parse_change_state);
}
static void
gst_vcd_parse_init (GstVcdParse * vcd, GstVcdParseClass * klass)
{
vcd->sinkpad = gst_pad_new_from_static_template (&sink_factory, "sink");
gst_pad_set_chain_function (vcd->sinkpad,
GST_DEBUG_FUNCPTR (gst_vcd_parse_chain));
gst_pad_set_event_function (vcd->sinkpad,
GST_DEBUG_FUNCPTR (gst_vcd_parse_sink_event));
gst_element_add_pad (GST_ELEMENT (vcd), vcd->sinkpad);
vcd->srcpad = gst_pad_new_from_static_template (&src_factory, "src");
gst_pad_set_event_function (vcd->srcpad,
GST_DEBUG_FUNCPTR (gst_vcd_parse_src_event));
gst_pad_set_query_function (vcd->srcpad,
GST_DEBUG_FUNCPTR (gst_vcd_parse_src_query));
gst_pad_use_fixed_caps (vcd->srcpad);
gst_pad_set_caps (vcd->srcpad,
gst_static_pad_template_get_caps (&src_factory));
gst_element_add_pad (GST_ELEMENT (vcd), vcd->srcpad);
}
/* These conversion functions assume there's no junk between sectors */
static gint64
gst_vcd_parse_get_out_offset (gint64 in_offset)
{
gint64 out_offset, chunknum, rest;
if (in_offset == -1)
return -1;
if (G_UNLIKELY (in_offset < -1)) {
GST_WARNING ("unexpected/invalid in_offset %" G_GINT64_FORMAT, in_offset);
return in_offset;
}
chunknum = in_offset / GST_CDXA_SECTOR_SIZE;
rest = in_offset % GST_CDXA_SECTOR_SIZE;
out_offset = chunknum * GST_CDXA_DATA_SIZE;
if (rest > GST_CDXA_HEADER_SIZE) {
if (rest >= GST_CDXA_HEADER_SIZE + GST_CDXA_DATA_SIZE)
out_offset += GST_CDXA_DATA_SIZE;
else
out_offset += rest - GST_CDXA_HEADER_SIZE;
}
GST_LOG ("transformed in_offset %" G_GINT64_FORMAT " to out_offset %"
G_GINT64_FORMAT, in_offset, out_offset);
return out_offset;
}
static gint64
gst_vcd_parse_get_in_offset (gint64 out_offset)
{
gint64 in_offset, chunknum, rest;
if (out_offset == -1)
return -1;
if (G_UNLIKELY (out_offset < -1)) {
GST_WARNING ("unexpected/invalid out_offset %" G_GINT64_FORMAT, out_offset);
return out_offset;
}
chunknum = out_offset / GST_CDXA_DATA_SIZE;
rest = out_offset % GST_CDXA_DATA_SIZE;
in_offset = chunknum * GST_CDXA_SECTOR_SIZE;
if (rest > 0)
in_offset += GST_CDXA_HEADER_SIZE + rest;
GST_LOG ("transformed out_offset %" G_GINT64_FORMAT " to in_offset %"
G_GINT64_FORMAT, out_offset, in_offset);
return in_offset;
}
static gboolean
gst_vcd_parse_src_query (GstPad * pad, GstQuery * query)
{
GstVcdParse *vcd = GST_VCD_PARSE (gst_pad_get_parent (pad));
gboolean res = FALSE;
switch (GST_QUERY_TYPE (query)) {
case GST_QUERY_DURATION:{
GstFormat format;
gint64 dur;
/* first try upstream */
if (!gst_pad_query_default (pad, query))
break;
/* we can only handle BYTES */
gst_query_parse_duration (query, &format, &dur);
if (format != GST_FORMAT_BYTES)
break;
gst_query_set_duration (query, GST_FORMAT_BYTES,
gst_vcd_parse_get_out_offset (dur));
res = TRUE;
break;
}
case GST_QUERY_POSITION:{
GstFormat format;
gint64 pos;
/* first try upstream */
if (!gst_pad_query_default (pad, query))
break;
/* we can only handle BYTES */
gst_query_parse_position (query, &format, &pos);
if (format != GST_FORMAT_BYTES)
break;
gst_query_set_position (query, GST_FORMAT_BYTES,
gst_vcd_parse_get_out_offset (pos));
res = TRUE;
break;
}
default:
res = gst_pad_query_default (pad, query);
break;
}
gst_object_unref (vcd);
return res;
}
static gboolean
gst_vcd_parse_sink_event (GstPad * pad, GstEvent * event)
{
GstVcdParse *vcd = GST_VCD_PARSE (gst_pad_get_parent (pad));
gboolean res;
switch (GST_EVENT_TYPE (event)) {
case GST_EVENT_NEWSEGMENT:{
GstFormat format;
gboolean update;
gdouble rate, applied_rate;
gint64 start, stop, position;
gst_event_parse_new_segment_full (event, &update, &rate, &applied_rate,
&format, &start, &stop, &position);
if (format == GST_FORMAT_BYTES) {
gst_event_unref (event);
event = gst_event_new_new_segment_full (update, rate, applied_rate,
GST_FORMAT_BYTES, gst_vcd_parse_get_out_offset (start),
gst_vcd_parse_get_out_offset (stop), position);
} else {
GST_WARNING_OBJECT (vcd, "newsegment event in non-byte format");
}
res = gst_pad_event_default (pad, event);
break;
}
case GST_EVENT_FLUSH_START:
gst_adapter_clear (vcd->adapter);
/* fall through */
default:
res = gst_pad_event_default (pad, event);
break;
}
gst_object_unref (vcd);
return res;
}
static gboolean
gst_vcd_parse_src_event (GstPad * pad, GstEvent * event)
{
GstVcdParse *vcd = GST_VCD_PARSE (gst_pad_get_parent (pad));
gboolean res;
switch (GST_EVENT_TYPE (event)) {
case GST_EVENT_SEEK:{
GstSeekType start_type, stop_type;
GstSeekFlags flags;
GstFormat format;
gdouble rate;
gint64 start, stop;
gst_event_parse_seek (event, &rate, &format, &flags, &start_type,
&start, &stop_type, &stop);
if (format == GST_FORMAT_BYTES) {
gst_event_unref (event);
if (start_type != GST_SEEK_TYPE_NONE)
start = gst_vcd_parse_get_in_offset (start);
if (stop_type != GST_SEEK_TYPE_NONE)
stop = gst_vcd_parse_get_in_offset (stop);
event = gst_event_new_seek (rate, GST_FORMAT_BYTES, flags, start_type,
start, stop_type, stop);
} else {
GST_WARNING_OBJECT (vcd, "seek event in non-byte format");
}
res = gst_pad_event_default (pad, event);
break;
}
default:
res = gst_pad_event_default (pad, event);
break;
}
gst_object_unref (vcd);
return res;
}
/* -1 = no sync (discard buffer),
* otherwise offset indicates sync point in buffer */
static gint
gst_vcd_parse_sync (const guint8 * data, guint size)
{
const guint8 sync_marker[12] = { 0x00, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0x00
};
guint off = 0;
while (size >= 12) {
if (memcmp (data, sync_marker, 12) == 0)
return off;
--size;
++data;
++off;
}
return -1;
}
static GstFlowReturn
gst_vcd_parse_chain (GstPad * pad, GstBuffer * buf)
{
GstVcdParse *vcd = GST_VCD_PARSE (GST_PAD_PARENT (pad));
GstFlowReturn flow = GST_FLOW_OK;
gst_adapter_push (vcd->adapter, buf);
buf = NULL;
while (gst_adapter_available (vcd->adapter) >= GST_CDXA_SECTOR_SIZE) {
const guint8 *data;
guint8 header[4 + 8];
gint sync_offset;
/* find sync (we could peek any size though really) */
data = gst_adapter_peek (vcd->adapter, GST_CDXA_SECTOR_SIZE);
sync_offset = gst_vcd_parse_sync (data, GST_CDXA_SECTOR_SIZE);
GST_LOG_OBJECT (vcd, "sync offset = %d", sync_offset);
if (sync_offset < 0) {
gst_adapter_flush (vcd->adapter, GST_CDXA_SECTOR_SIZE - 12);
continue; /* try again */
}
gst_adapter_flush (vcd->adapter, sync_offset);
if (gst_adapter_available (vcd->adapter) < GST_CDXA_SECTOR_SIZE) {
GST_LOG_OBJECT (vcd, "not enough data in adapter, waiting for more");
break;
}
GST_LOG_OBJECT (vcd, "have full sector");
/* have one sector: a sector is 2352 bytes long and is composed of:
*
* +-------------------------------------------------------+
* ! sync ! header ! subheader ! data ... ! edc !
* ! 12 bytes ! 4 bytes ! 8 bytes ! 2324 bytes ! 4 bytes !
* +-------------------------------------------------------+
*
* We strip the data out of it and send it to the srcpad.
*
* sync : 00 FF FF FF FF FF FF FF FF FF FF 00
* header : hour minute second mode
* sub-header : track channel sub_mode coding repeat (4 bytes)
* edc : checksum
*/
/* Skip CDXA header and edc footer, only keep data in the middle */
gst_adapter_copy (vcd->adapter, header, 12, sizeof (header));
gst_adapter_flush (vcd->adapter, GST_CDXA_HEADER_SIZE);
buf = gst_adapter_take_buffer (vcd->adapter, GST_CDXA_DATA_SIZE);
gst_adapter_flush (vcd->adapter, 4);
/* we could probably do something clever to keep track of buffer offsets */
buf = gst_buffer_make_metadata_writable (buf);
GST_BUFFER_OFFSET (buf) = GST_BUFFER_OFFSET_NONE;
GST_BUFFER_TIMESTAMP (buf) = GST_CLOCK_TIME_NONE;
gst_buffer_set_caps (buf, GST_PAD_CAPS (vcd->srcpad));
flow = gst_pad_push (vcd->srcpad, buf);
buf = NULL;
if (G_UNLIKELY (flow != GST_FLOW_OK)) {
GST_DEBUG_OBJECT (vcd, "flow: %s", gst_flow_get_name (flow));
break;
}
}
return flow;
}
static GstStateChangeReturn
gst_vcd_parse_change_state (GstElement * element, GstStateChange transition)
{
GstStateChangeReturn res = GST_STATE_CHANGE_SUCCESS;
GstVcdParse *vcd = GST_VCD_PARSE (element);
switch (transition) {
case GST_STATE_CHANGE_READY_TO_PAUSED:
vcd->adapter = gst_adapter_new ();
break;
default:
break;
}
res = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
switch (transition) {
case GST_STATE_CHANGE_PAUSED_TO_READY:
case GST_STATE_CHANGE_READY_TO_NULL:
if (vcd->adapter) {
g_object_unref (vcd->adapter);
vcd->adapter = NULL;
}
break;
default:
break;
}
return res;
}