gstreamer/gst/mpegstream/gstmpegpacketize.c

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/* Gnome-Streamer
* 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.
*/
/*#define GST_DEBUG_ENABLED */
#include <gstmpegpacketize.h>
GstMPEGPacketize*
gst_mpeg_packetize_new (GstByteStream *bs)
{
GstMPEGPacketize *new;
g_return_val_if_fail (bs != NULL, NULL);
new = g_malloc (sizeof (GstMPEGPacketize));
new->id = 0;
new->bs = bs;
new->MPEG2 = FALSE;
return new;
}
void
gst_mpeg_packetize_destroy (GstMPEGPacketize *packetize)
{
g_return_if_fail (packetize != NULL);
g_free (packetize);
}
static GstData*
parse_packhead (GstMPEGPacketize * packetize)
{
gint length = 8 + 4;
guint8 *buf;
GstBuffer *outbuf;
GST_DEBUG (0, "packetize: in parse_packhead\n");
buf = gst_bytestream_peek_bytes (packetize->bs, length);
if (!buf) return NULL;
buf += 4;
GST_DEBUG (0, "code %02x\n", *buf);
/* start parsing the stream */
if ((*buf & 0xf0) == 0x40) {
GST_DEBUG (0, "packetize::parse_packhead setting mpeg2\n");
packetize->MPEG2 = TRUE;
length += 2;
buf = gst_bytestream_peek_bytes (packetize->bs, length);
if (!buf) return NULL;
}
else {
GST_DEBUG (0, "packetize::parse_packhead setting mpeg1\n");
packetize->MPEG2 = FALSE;
}
outbuf = gst_bytestream_read (packetize->bs, length);
if (!outbuf) return NULL;
return GST_DATA (outbuf);
}
static inline GstData*
parse_generic (GstMPEGPacketize *packetize)
{
guint16 length;
GstByteStream *bs = packetize->bs;
guchar *buf;
GstBuffer *outbuf;
GST_DEBUG (0, "packetize: in parse_syshead\n");
buf = gst_bytestream_peek_bytes (bs, 2 + 4);
if (!buf) return NULL;
buf += 4;
length = GUINT16_FROM_BE (*(guint16 *) buf);
GST_DEBUG (0, "packetize: header_length %d\n", length);
outbuf = gst_bytestream_read (packetize->bs, 2 + length + 4);
if (!outbuf) 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;
const gint chunksize = 4096;
buf = gst_bytestream_peek_bytes (bs, chunksize);
if (!buf)
return FALSE;
offset = 4;
code = GUINT32_FROM_BE (*((guint32 *)buf));
GST_DEBUG (0, "code = %08x\n", code);
while ((code & 0xffffff00) != 0x100L) {
code = (code << 8) | buf[offset++];
GST_DEBUG (0, " code = %08x\n", code);
/* g_print (" code = %08x\n", code); */
if (offset == chunksize) {
if (!gst_bytestream_flush (bs, offset))
return FALSE;
buf = gst_bytestream_peek_bytes (bs, chunksize);
if (!buf)
return FALSE;
offset = 0;
}
}
packetize->id = code & 0xff;
if (offset > 4) {
if (!gst_bytestream_flush (bs, offset - 4))
return FALSE;
}
return TRUE;
}
GstData*
gst_mpeg_packetize_read (GstMPEGPacketize *packetize)
{
gboolean got_event = FALSE;
GstData *outbuf = NULL;
while (outbuf == NULL) {
if (!find_start_code (packetize))
got_event = TRUE;
else {
GST_DEBUG (0, "packetize: have chunk 0x%02X\n",packetize->id);
switch (packetize->id) {
case 0xBA:
outbuf = parse_packhead (packetize);
if (!outbuf)
got_event = TRUE;
break;
case 0xBB:
outbuf = parse_generic (packetize);
if (!outbuf)
got_event = TRUE;
break;
default:
if (packetize->MPEG2 && ((packetize->id < 0xBD) || (packetize->id > 0xFE))) {
g_warning ("packetize: ******** unknown id 0x%02X",packetize->id);
}
else {
outbuf = parse_generic (packetize);
if (!outbuf)
got_event = TRUE;
}
}
}
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_bytestream_flush_fast (packetize->bs, remaining);
break;
}
return GST_DATA (event);
}
}
return outbuf;
}