gstreamer/gst/mpegstream/gstmpegpacketize.c

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/* GStreamer
* Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
*
* 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.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
/*#define GST_DEBUG_ENABLED */
#include <gstmpegpacketize.h>
GstMPEGPacketize*
gst_mpeg_packetize_new (GstPad *pad, GstMPEGPacketizeType type)
{
GstMPEGPacketize *new;
g_return_val_if_fail (pad != NULL, NULL);
g_return_val_if_fail (GST_IS_PAD (pad), NULL);
new = g_malloc (sizeof (GstMPEGPacketize));
gst_object_ref (GST_OBJECT (pad));
new->resync = TRUE;
new->id = 0;
new->pad = pad;
new->bs = gst_bytestream_new (pad);
new->MPEG2 = FALSE;
new->type = type;
return new;
}
void
gst_mpeg_packetize_destroy (GstMPEGPacketize *packetize)
{
g_return_if_fail (packetize != NULL);
gst_bytestream_destroy (packetize->bs);
gst_object_unref (GST_OBJECT (packetize->pad));
g_free (packetize);
}
static GstData*
parse_packhead (GstMPEGPacketize *packetize)
{
gint length = 8 + 4;
guint8 *buf;
GstBuffer *outbuf;
guint32 got_bytes;
GST_DEBUG ("packetize: in parse_packhead");
got_bytes = gst_bytestream_peek_bytes (packetize->bs, &buf, length);
if (got_bytes < length)
return NULL;
buf += 4;
GST_DEBUG ("code %02x", *buf);
/* start parsing the stream */
if ((*buf & 0xc0) == 0x40) {
GST_DEBUG ("packetize::parse_packhead setting mpeg2");
packetize->MPEG2 = TRUE;
length += 2;
got_bytes = gst_bytestream_peek_bytes (packetize->bs, &buf, length);
if (got_bytes < length)
return NULL;
}
else {
GST_DEBUG ("packetize::parse_packhead setting mpeg1");
packetize->MPEG2 = FALSE;
}
got_bytes = gst_bytestream_read (packetize->bs, &outbuf, length);
if (got_bytes < length)
return NULL;
return GST_DATA (outbuf);
}
static GstData*
parse_end (GstMPEGPacketize *packetize)
{
guint32 got_bytes;
GstBuffer *outbuf;
got_bytes = gst_bytestream_read (packetize->bs, &outbuf, 4);
if (got_bytes < 4)
return NULL;
return GST_DATA (outbuf);
}
static inline GstData*
parse_generic (GstMPEGPacketize *packetize)
{
GstByteStream *bs = packetize->bs;
guchar *buf;
GstBuffer *outbuf;
guint32 got_bytes;
gint16 length = 6;
GST_DEBUG ("packetize: in parse_generic");
got_bytes = gst_bytestream_peek_bytes (bs, (guint8**)&buf, length);
if (got_bytes < 6)
return NULL;
buf += 4;
length += GUINT16_FROM_BE (*(guint16 *) buf);
GST_DEBUG ("packetize: header_length %d", length);
got_bytes = gst_bytestream_read (packetize->bs, &outbuf, length);
if (got_bytes < length)
return NULL;
return GST_DATA (outbuf);
}
static inline GstData*
parse_chunk (GstMPEGPacketize *packetize)
{
GstByteStream *bs = packetize->bs;
guchar *buf;
gint offset;
guint32 code;
gint chunksize;
GstBuffer *outbuf = NULL;
chunksize = gst_bytestream_peek_bytes (bs, (guint8**)&buf, 4096);
if (chunksize == 0)
return NULL;
offset = 4;
code = GUINT32_FROM_BE (*((guint32 *)(buf+offset)));
GST_DEBUG ("code = %08x", code);
while ((code & 0xffffff00) != 0x100L) {
code = (code << 8) | buf[offset++];
GST_DEBUG (" code = %08x", code);
if (offset == chunksize) {
chunksize = gst_bytestream_peek_bytes (bs, (guint8**)&buf, offset + 4096);
if (chunksize == 0)
return NULL;
chunksize += offset;
}
}
if (offset > 4) {
chunksize = gst_bytestream_read (bs, &outbuf, offset-4);
if (chunksize == 0)
return NULL;
}
return GST_DATA (outbuf);
}
/* FIXME mmx-ify me */
static inline gboolean
find_start_code (GstMPEGPacketize *packetize)
{
GstByteStream *bs = packetize->bs;
guchar *buf;
gint offset;
guint32 code;
gint chunksize;
chunksize = gst_bytestream_peek_bytes (bs, (guint8**)&buf, 4096);
if (chunksize < 5)
return FALSE;
offset = 4;
code = GUINT32_FROM_BE (*((guint32 *)(buf)));
GST_DEBUG ("code = %08x %p %08x", code, buf, chunksize);
while ((code & 0xffffff00) != 0x100L) {
code = (code << 8) | buf[offset++];
GST_DEBUG (" code = %08x %p %08x", code, buf, chunksize);
if (offset == chunksize) {
gst_bytestream_flush_fast (bs, offset);
chunksize = gst_bytestream_peek_bytes (bs, (guint8**)&buf, 4096);
if (chunksize == 0)
return FALSE;
offset = 0;
}
}
packetize->id = code & 0xff;
if (offset > 4) {
gst_bytestream_flush_fast (bs, offset - 4);
}
return TRUE;
}
GstData*
gst_mpeg_packetize_read (GstMPEGPacketize *packetize)
{
gboolean got_event = FALSE;
GstData *outbuf = NULL;
g_return_val_if_fail (packetize != NULL, NULL);
while (outbuf == NULL) {
if (!find_start_code (packetize))
got_event = TRUE;
else {
GST_DEBUG ("packetize: have chunk 0x%02X", packetize->id);
if (packetize->type == GST_MPEG_PACKETIZE_SYSTEM) {
if (packetize->resync) {
if (packetize->id != PACK_START_CODE) {
gst_bytestream_flush_fast (packetize->bs, 4);
continue;
}
packetize->resync = FALSE;
}
switch (packetize->id) {
case PACK_START_CODE:
outbuf = parse_packhead (packetize);
if (!outbuf)
got_event = TRUE;
break;
case SYS_HEADER_START_CODE:
outbuf = parse_generic (packetize);
if (!outbuf)
got_event = TRUE;
break;
case ISO11172_END_START_CODE:
outbuf = parse_end (packetize);
if (!outbuf)
got_event = TRUE;
break;
default:
if (packetize->MPEG2 && ((packetize->id < 0xBD) || (packetize->id > 0xFE))) {
gst_bytestream_flush (packetize->bs, 4);
g_warning ("packetize: ******** unknown id 0x%02X",packetize->id);
}
else {
outbuf = parse_generic (packetize);
if (!outbuf)
got_event = TRUE;
}
}
}
else if (packetize->type == GST_MPEG_PACKETIZE_VIDEO) {
outbuf = parse_chunk (packetize);
}
else {
g_assert_not_reached ();
}
}
if (got_event) {
guint32 remaining;
GstEvent *event;
gint etype;
gst_bytestream_get_status (packetize->bs, &remaining, &event);
etype = event? GST_EVENT_TYPE (event) : GST_EVENT_EOS;
switch (etype) {
case GST_EVENT_DISCONTINUOUS:
GST_DEBUG ("packetize: discont\n");
gst_bytestream_flush_fast (packetize->bs, remaining);
break;
}
return GST_DATA (event);
}
}
return outbuf;
}