mirrors/gstreamer
mirrors/gstreamer
1
1
Fork 0
mirror of https://gitlab.freedesktop.org/gstreamer/gstreamer.git synced 2024-11-23 18:21:04 +00:00
Code Issues 1 Projects Releases Wiki Activity

j2kpay: use SOP markers to split bitstream

Browse source 
When parsing the bitstream, look for SOP markers because we are allowed to split
packets on those marker boundaries.
Rework the parsing code a little so that we can pack multiple Packetization
units in one RTP packet.
This commit is contained in:
Wim Taymans 2010-12-02 17:53:42 +01:00
parent 29363d6068
commit 005e27fa79
1 changed files with 178 additions and 73 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

251
gst/rtp/gstrtpj2kpay.c
View file

@ -72,6 +72,8 @@ typedef enum
J2K_MARKER = 0xFF,
J2K_MARKER_SOC = 0x4F,
J2K_MARKER_SOT = 0x90,
J2K_MARKER_SOP = 0x91,
J2K_MARKER_SOD = 0x93,
J2K_MARKER_EOC = 0xD9
} RtpJ2KMarker;
@ -226,64 +228,126 @@ gst_rtp_j2k_pay_scan_marker (const guint8 * data, guint size, guint * offset)
while ((data[(*offset)++] != J2K_MARKER) && ((*offset) < size));
if (G_UNLIKELY ((*offset) >= size)) {
GST_LOG ("end of data, return EOC");
return J2K_MARKER_EOC;
} else {
guint8 marker = data[(*offset)++];
GST_LOG ("found %02x marker", marker);
return marker;
}
}
typedef struct
{
RtpJ2KHeader header;
gboolean bitstream;
guint n_tiles;
guint next_sot;
gboolean force_packet;
} RtpJ2KState;
static guint
find_pu_end (GstRtpJ2KPay * pay, const guint8 * data, guint size,
guint offset, RtpJ2KHeader * header)
guint offset, RtpJ2KState * state)
{
gboolean cut_sop = FALSE;
RtpJ2KMarker marker;
/* parse the j2k header for 'start of codestream' */
GST_LOG_OBJECT (pay, "checking from offset %u", offset);
while (offset < size) {
GST_LOG_OBJECT (pay, "checking from offset %u", offset);
switch (gst_rtp_j2k_pay_scan_marker (data, size, &offset)) {
case J2K_MARKER_SOC:
GST_DEBUG_OBJECT (pay, "found SOC at %u", offset);
header->MHF = 1;
break;
case J2K_MARKER_SOT:
{
guint len, Psot;
marker = gst_rtp_j2k_pay_scan_marker (data, size, &offset);
GST_DEBUG_OBJECT (pay, "found SOT at %u", offset);
/* we found SOT but also had a header first */
if (header->MHF)
return offset - 2;
/* parse SOT but do some sanity checks first */
len = gst_rtp_j2k_pay_header_size (data, offset);
GST_DEBUG_OBJECT (pay, "SOT length %u", len);
if (len < 8)
return size;
if (offset + len >= size)
return size;
/* we have a valid tile number now, keep it in the header */
header->T = 0;
header->tile = GST_READ_UINT16_BE (&data[offset + 2]);
/* get offset of next tile, if it's 0, it goes all the way to the end of
* the data */
Psot = GST_READ_UINT32_BE (&data[offset + 4]);
if (Psot == 0)
offset = size;
else
offset += Psot;
GST_DEBUG_OBJECT (pay, "Isot %u, Psot %u", header->tile, Psot);
break;
if (state->bitstream) {
/* parsing bitstream, only look for SOP */
switch (marker) {
case J2K_MARKER_SOP:
GST_LOG_OBJECT (pay, "found SOP at %u", offset);
if (cut_sop)
return offset - 2;
cut_sop = TRUE;
break;
default:
if (offset >= state->next_sot) {
GST_LOG_OBJECT (pay, "reached next SOT at %u", offset);
state->bitstream = FALSE;
state->force_packet = TRUE;
if (marker == J2K_MARKER_EOC)
/* include EOC */
return state->next_sot + 2;
else
return state->next_sot;
}
break;
}
} else {
switch (marker) {
case J2K_MARKER_SOC:
GST_LOG_OBJECT (pay, "found SOC at %u", offset);
state->header.MHF = 1;
break;
case J2K_MARKER_SOT:
{
guint len, Psot;
GST_LOG_OBJECT (pay, "found SOT at %u", offset);
/* we found SOT but also had a header first */
if (state->header.MHF) {
state->force_packet = TRUE;
return offset - 2;
}
/* parse SOT but do some sanity checks first */
len = gst_rtp_j2k_pay_header_size (data, offset);
GST_LOG_OBJECT (pay, "SOT length %u", len);
if (len < 8)
return size;
if (offset + len >= size)
return size;
if (state->n_tiles == 0)
/* first tile, T is valid */
state->header.T = 0;
else
/* more tiles, T becomes invalid */
state->header.T = 1;
state->header.tile = GST_READ_UINT16_BE (&data[offset + 2]);
state->n_tiles++;
/* get offset of next tile, if it's 0, it goes all the way to the end of
* the data */
Psot = GST_READ_UINT32_BE (&data[offset + 4]);
if (Psot == 0)
state->next_sot = size;
else
state->next_sot = offset - 2 + Psot;
offset += len;
GST_LOG_OBJECT (pay, "Isot %u, Psot %u, next %u", state->header.tile,
Psot, state->next_sot);
break;
}
case J2K_MARKER_SOD:
GST_LOG_OBJECT (pay, "found SOD at %u", offset);
/* can't have more tiles now */
state->n_tiles = 0;
/* go to bitstream parsing */
state->bitstream = TRUE;
/* cut at the next SOP or else include all data */
cut_sop = TRUE;
/* force a new packet when we see SOP, this can be optional but the
* spec recommends packing headers separately */
state->force_packet = TRUE;
break;
case J2K_MARKER_EOC:
GST_LOG_OBJECT (pay, "found EOC at %u", offset);
return offset;
default:
{
guint len = gst_rtp_j2k_pay_header_size (data, offset);
GST_LOG_OBJECT (pay, "skip 0x%02x len %u", marker, len);
offset += len;
break;
}
}
case J2K_MARKER_EOC:
GST_DEBUG_OBJECT (pay, "found EOC");
return offset;
default:
offset += gst_rtp_j2k_pay_header_size (data, offset);
break;
}
}
GST_DEBUG_OBJECT (pay, "reached end of data");
@ -297,13 +361,14 @@ gst_rtp_j2k_pay_handle_buffer (GstBaseRTPPayload * basepayload,
GstRtpJ2KPay *pay;
GstClockTime timestamp;
GstFlowReturn ret = GST_FLOW_ERROR;
RtpJ2KHeader j2k_header;
RtpJ2KState state;
GstBufferList *list = NULL;
GstBufferListIterator *it = NULL;
guint8 *data;
guint size;
guint mtu;
guint mtu, max_size;
guint offset;
guint end, pos;
pay = GST_RTP_J2K_PAY (basepayload);
mtu = GST_BASE_RTP_PAYLOAD_MTU (pay);
@ -311,47 +376,87 @@ gst_rtp_j2k_pay_handle_buffer (GstBaseRTPPayload * basepayload,
size = GST_BUFFER_SIZE (buffer);
data = GST_BUFFER_DATA (buffer);
timestamp = GST_BUFFER_TIMESTAMP (buffer);
offset = 0;
offset = pos = end = 0;
GST_LOG_OBJECT (pay, "got buffer size %u, timestamp %" GST_TIME_FORMAT, size,
GST_TIME_ARGS (timestamp));
/* do some header defaults first */
j2k_header.tp = 0; /* only progressive scan */
j2k_header.MHF = 0; /* no header */
j2k_header.mh_id = 0; /* always 0 for now */
j2k_header.T = 1; /* invalid tile */
j2k_header.priority = 255; /* always 255 for now */
j2k_header.tile = 0; /* no tile number */
j2k_header.reserved = 0;
state.header.tp = 0; /* only progressive scan */
state.header.MHF = 0; /* no header */
state.header.mh_id = 0; /* always 0 for now */
state.header.T = 1; /* invalid tile */
state.header.priority = 255; /* always 255 for now */
state.header.tile = 0; /* no tile number */
state.header.reserved = 0;
state.bitstream = FALSE;
state.n_tiles = 0;
state.next_sot = 0;
state.force_packet = FALSE;
if (pay->buffer_list) {
list = gst_buffer_list_new ();
it = gst_buffer_list_iterate (list);
}
/* get max packet length */
max_size = gst_rtp_buffer_calc_payload_len (mtu - HEADER_SIZE, 0, 0);
do {
GstBuffer *outbuf;
guint8 *header;
guint pu_size, end;
guint payload_size;
guint pu_size;
/* scan next packetization unit and fill in the header */
end = find_pu_end (pay, data, size, offset, &j2k_header);
pu_size = end - offset;
/* try to pack as much as we can */
do {
/* see how much we have scanned already */
pu_size = end - offset;
GST_DEBUG_OBJECT (pay, "scanned pu size %u", pu_size);
GST_DEBUG_OBJECT (pay, "pu of size %u", pu_size);
/* we need to make a new packet */
if (state.force_packet) {
GST_DEBUG_OBJECT (pay, "need to force a new packet");
state.force_packet = FALSE;
pos = end;
break;
}
/* else see if we have enough */
if (pu_size > max_size) {
if (pos != offset)
/* the packet became too large, use previous scanpos */
pu_size = pos - offset;
else
/* the already scanned data was already too big, make sure we start
* scanning from the last searched position */
pos = end;
GST_DEBUG_OBJECT (pay, "max size exceeded pu_size %u", pu_size);
break;
}
pos = end;
/* scan next packetization unit and fill in the header */
end = find_pu_end (pay, data, size, pos, &state);
} while (TRUE);
while (pu_size > 0) {
guint packet_size, payload_size, data_size;
guint packet_size, data_size;
/* calculate the packet size */
packet_size =
gst_rtp_buffer_calc_packet_len (pu_size + HEADER_SIZE, 0, 0);
GST_DEBUG_OBJECT (pay, "needed packet size %u", packet_size);
if (packet_size > mtu) {
GST_DEBUG_OBJECT (pay, "needed packet size %u clamped to MTU %u",
packet_size, mtu);
packet_size = mtu;
} else {
GST_DEBUG_OBJECT (pay, "needed packet size %u fits in MTU %u",
packet_size, mtu);
}
/* make sure it fits the MTU */
packet_size = (packet_size < mtu ? packet_size : mtu);
/* get total payload size and data size */
payload_size = gst_rtp_buffer_calc_payload_len (packet_size, 0, 0);
data_size = payload_size - HEADER_SIZE;
@ -371,13 +476,13 @@ gst_rtp_j2k_pay_handle_buffer (GstBaseRTPPayload * basepayload,
pu_size -= data_size;
if (pu_size == 0) {
/* reached the end of a packetization unit */
if (j2k_header.MHF) {
if (state.header.MHF) {
/* we were doing a header, see if all fit in one packet or if
* we had to fragment it */
if (offset == 0)
j2k_header.MHF = 3;
state.header.MHF = 3;
else
j2k_header.MHF = 2;
state.header.MHF = 2;
}
if (end >= size)
gst_rtp_buffer_set_marker (outbuf, TRUE);
@ -385,12 +490,12 @@ gst_rtp_j2k_pay_handle_buffer (GstBaseRTPPayload * basepayload,
/* copy the header and push the packet */
#if (G_BYTE_ORDER == G_LITTLE_ENDIAN)
j2k_header.offset = ((offset & 0x0000FF) << 16) |
state.header.offset = ((offset & 0x0000FF) << 16) |
((offset & 0xFF0000) >> 16) | (offset & 0x00FF00);
#else
j2k_header.offset = offset;
state.header.offset = offset;
#endif
memcpy (header, &j2k_header, HEADER_SIZE);
memcpy (header, &state.header, HEADER_SIZE);
if (pay->buffer_list) {
GstBuffer *paybuf;
@ -414,13 +519,13 @@ gst_rtp_j2k_pay_handle_buffer (GstBaseRTPPayload * basepayload,
}
/* reset header for next round */
j2k_header.MHF = 0;
j2k_header.T = 1;
j2k_header.tile = 0;
state.header.MHF = 0;
state.header.T = 1;
state.header.tile = 0;
offset += data_size;
}
offset = end;
offset = pos;
} while (offset < size);
done: