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h264: Remove unneeded errata checks. 

Some Microsoft errata were caused by bad decoding and were not actually
problems.  Remove the unneeded tests and expert information.
Add PRID ranges values to Layer Presence bytes.

Change-Id: I0b2b555bc448f0b4ee142b2920ae4e37d54ccab4
Reviewed-on: https://code.wireshark.org/review/2958
Reviewed-by: Anders Broman <a.broman58@gmail.com>
This commit is contained in:
Britt McKinley 2014-07-09 10:45:32 -04:00 committed by Anders Broman
parent bb9a25177c
commit b2bf078d52
1 changed files with 9 additions and 48 deletions
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57
epan/dissectors/packet-h264.c
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@ -259,11 +259,8 @@ static int ett_h264_ms_layer_description = -1;
static int ett_h264_ms_crop_data = -1;
static expert_field ei_h264_undecoded = EI_INIT;
static expert_field ei_h264_ms_layout_missing_presence = EI_INIT;
static expert_field ei_h264_ms_layout_wrong_length = EI_INIT;
static expert_field ei_h264_bad_nal_length = EI_INIT;
static expert_field ei_h264_ms_sei_extra_data = EI_INIT;
static expert_field ei_h264_sei_invalid_length = EI_INIT;
/* The dynamic payload type range which will be dissected as H.264 */
@ -1372,33 +1369,20 @@ h264_user_data_unregistered(proto_tree *tree, tvbuff_t *tvb, packet_info *pinfo
/* Loop through the layer presence bytes 0-7 */
for (i = 0; i < 8 ; i++)
{
proto_tree_add_item (tree, hf_h264_sei_ms_lpb, tvb, offset, 1, ENC_BIG_ENDIAN);
item = proto_tree_add_item (tree, hf_h264_sei_ms_lpb, tvb, offset, 1, ENC_BIG_ENDIAN);
proto_item_append_text (item, " PRID %2d - %2d", (i+1)*8-1, i*8);
offset++;
}
/* Get the presence bit for the layer description.
* NOTE: This byte is supposed to be in the structure according to the spec but seems to be missing in the Microsoft implementation.
* So to determine if it is there check for a value less than or equal to 1. When Microsoft forgets to put it in the length is next and that
* has a minimum size of 16.
*/
p_flag = tvb_get_guint8 (tvb, offset);
if (p_flag <= 1)
{
proto_tree_add_item (tree, hf_h264_sei_ms_layout_p, tvb, offset, 1, ENC_BIG_ENDIAN);
offset++;
}
else
{
/* When it is missing act like it was set to 1. */
proto_tree_add_expert(tree, pinfo, &ei_h264_ms_layout_missing_presence, tvb, offset, 0);
p_flag = 1;
}
proto_tree_add_item (tree, hf_h264_sei_ms_layout_p, tvb, offset, 1, ENC_BIG_ENDIAN);
offset++;
if (p_flag == 1)
{
ld_size = tvb_get_guint8 (tvb, offset);
proto_tree_add_item (tree, hf_h264_sei_ms_layout_ldsize, tvb, offset, 1, ENC_BIG_ENDIAN);
offset++;
/* MS Errata - Microsoft seems to be setting the LD size to 1 but then including 2 layer descriptions
* To compensate for that keep decoding layers as long as there are 16 or more bytes left in the SEI message.
/* MS Errata - Microsoft seems to be setting the LD size to 16 but then including 2 layer descriptions which should be 32
* To compensate for that, keep decoding layers as long as there are 16 or more bytes left in the SEI message.
*/
if (tvb_reported_length_remaining (tvb, offset) != ld_size)
{
@ -1422,13 +1406,6 @@ h264_user_data_unregistered(proto_tree *tree, tvbuff_t *tvb, packet_info *pinfo
proto_tree_add_item (h264_ms_layer_desc_tree, hf_h264_sei_ms_layer_desc_cb, tvb, offset + 13, 1, ENC_BIG_ENDIAN);
offset += 16;
}
if (tvb_reported_length_remaining (tvb, offset) != 0)
{
item = proto_tree_add_expert(tree, pinfo, &ei_h264_ms_sei_extra_data, tvb, offset, tvb_reported_length_remaining (tvb, offset));
proto_item_append_text(item," Extra %d bytes", tvb_reported_length_remaining (tvb, offset));
/* Skip over data. */
offset += tvb_reported_length_remaining (tvb, offset);
}
}
}
else if ( memcmp(&guid, &(ms_guids[MS_CROPPING]), sizeof(e_guid_t)) == 0)
@ -2092,7 +2069,6 @@ dissect_h264_pacsi(proto_tree *tree, tvbuff_t *tvb, packet_info *pinfo, gint off
tvbuff_t *nalu_tvb;
gboolean error = FALSE;
gboolean contains_sei = FALSE;
proto_item *item;
offset = dissect_h264_svc_nal_header_extension(tree, tvb, pinfo, offset);
@ -2129,18 +2105,6 @@ dissect_h264_pacsi(proto_tree *tree, tvbuff_t *tvb, packet_info *pinfo, gint off
while (tvb_reported_length_remaining(tvb, offset) > 0 && !error)
{
nal_unit_size = tvb_get_ntohs(tvb, offset);
/* Perform a sanity check on the value. */
if (nal_unit_size == 0 || nal_unit_size > tvb_reported_length_remaining(tvb, offset))
{
/* Microsoft has a bug where it doesn't put in the P flag byte in the Layout message, but sets the size as if is there, so the size is off by
* byte too many in the first SEI message. Back up one and then try again.
*/
item = proto_tree_add_expert(tree, pinfo, &ei_h264_sei_invalid_length, tvb, offset, 2);
proto_item_append_text (item, " Size is %d, Remaining:%d, Try backing up 1 byte.",
nal_unit_size, tvb_reported_length_remaining(tvb, offset));
offset--;
nal_unit_size = tvb_get_ntohs(tvb, offset);
}
proto_tree_add_item(tree, hf_h264_nalu_size, tvb, offset, 2, ENC_NA);
offset += 2;
@ -3465,17 +3429,17 @@ proto_register_h264(void)
NULL, HFILL }
},
{ &hf_h264_sei_ms_lpb,
{ "Stream Layer Presence", "h264.sei.ms.layout.lpb",
{ "Layer Presence", "h264.sei.ms.layout.lpb",
FT_UINT8, BASE_HEX, NULL, 0x0,
NULL, HFILL }
},
{ &hf_h264_sei_ms_layout_p,
{ "Stream Layer Description Presence", "h264.sei.ms.layout.p",
{ "Layer Description Present", "h264.sei.ms.layout.p",
FT_BOOLEAN, 8, NULL, 0x01,
NULL, HFILL }
},
{ &hf_h264_sei_ms_layout_ldsize,
{ "Stream Layer Description Size", "h264.sei.ms.layout.desc.ldsize",
{ "Layer Description Size", "h264.sei.ms.layout.desc.ldsize",
FT_UINT8, BASE_DEC, NULL, 0x0,
NULL, HFILL }
},
@ -3704,10 +3668,7 @@ proto_register_h264(void)
static ei_register_info ei[] = {
{ &ei_h264_undecoded, { "h264.undecoded", PI_UNDECODED, PI_WARN, "[Not decoded yet]", EXPFILL }},
{ &ei_h264_ms_layout_missing_presence, { "h264.ms_layout.missing_presence", PI_PROTOCOL, PI_WARN, "[Missing Presence Byte]", EXPFILL }},
{ &ei_h264_ms_layout_wrong_length, { "h264.ms_layout.wrong_length", PI_PROTOCOL, PI_WARN, "[Wrong Layer Description Table Length]", EXPFILL }},
{ &ei_h264_ms_sei_extra_data, { "h264.sei_extra_data", PI_PROTOCOL, PI_WARN, "[Extra data in SEI message]", EXPFILL }},
{ &ei_h264_sei_invalid_length, { "h264.sei_invalid_length", PI_PROTOCOL, PI_WARN, "[Bad SEI Unit Size in PACSI]", EXPFILL }},
{ &ei_h264_bad_nal_length, { "h264.bad_nalu_length", PI_MALFORMED, PI_ERROR, "[Bad NAL Unit Length]", EXPFILL }},
};