h264bsd_nal_unit.c revision 0c1bc742181ded4930842b46e9507372f0b1b963 
1/*
2 * Copyright (C) 2009 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17/*------------------------------------------------------------------------------
18
19    Table of contents
20
21     1. Include headers
22     2. External compiler flags
23     3. Module defines
24     4. Local function prototypes
25     5. Functions
26          h264bsdDecodeNalUnit
27
28------------------------------------------------------------------------------*/
29
30/*------------------------------------------------------------------------------
31    1. Include headers
32------------------------------------------------------------------------------*/
33
34#include "h264bsd_nal_unit.h"
35#include "h264bsd_util.h"
36
37/*------------------------------------------------------------------------------
38    2. External compiler flags
39--------------------------------------------------------------------------------
40
41--------------------------------------------------------------------------------
42    3. Module defines
43------------------------------------------------------------------------------*/
44
45/*------------------------------------------------------------------------------
46    4. Local function prototypes
47------------------------------------------------------------------------------*/
48
49/*------------------------------------------------------------------------------
50
51    Function name: h264bsdDecodeNalUnit
52
53        Functional description:
54            Decode NAL unit header information
55
56        Inputs:
57            pStrmData       pointer to stream data structure
58
59        Outputs:
60            pNalUnit        NAL unit header information is stored here
61
62        Returns:
63            HANTRO_OK       success
64            HANTRO_NOK      invalid NAL unit header information
65
66------------------------------------------------------------------------------*/
67
68u32 h264bsdDecodeNalUnit(strmData_t *pStrmData, nalUnit_t *pNalUnit)
69{
70
71/* Variables */
72
73    u32 tmp;
74
75/* Code */
76
77    ASSERT(pStrmData);
78    ASSERT(pNalUnit);
79    ASSERT(pStrmData->bitPosInWord == 0);
80
81    /* forbidden_zero_bit (not checked to be zero, errors ignored) */
82    tmp = h264bsdGetBits(pStrmData, 1);
83    /* Assuming that NAL unit starts from byte boundary �> don't have to check
84     * following 7 bits for END_OF_STREAM */
85    if (tmp == END_OF_STREAM)
86        return(HANTRO_NOK);
87
88    tmp = h264bsdGetBits(pStrmData, 2);
89    pNalUnit->nalRefIdc = tmp;
90
91    tmp = h264bsdGetBits(pStrmData, 5);
92    pNalUnit->nalUnitType = (nalUnitType_e)tmp;
93
94    /* data partitioning NAL units not supported */
95    if ( (tmp == 2) || (tmp == 3) || (tmp == 4) )
96    {
97        return(HANTRO_NOK);
98    }
99
100    /* nal_ref_idc shall not be zero for these nal_unit_types */
101    if ( ( (tmp == NAL_SEQ_PARAM_SET) || (tmp == NAL_PIC_PARAM_SET) ||
102           (tmp == NAL_CODED_SLICE_IDR) ) && (pNalUnit->nalRefIdc == 0) )
103    {
104        return(HANTRO_NOK);
105    }
106    /* nal_ref_idc shall be zero for these nal_unit_types */
107    else if ( ( (tmp == NAL_SEI) || (tmp == NAL_ACCESS_UNIT_DELIMITER) ||
108                (tmp == NAL_END_OF_SEQUENCE) || (tmp == NAL_END_OF_STREAM) ||
109                (tmp == NAL_FILLER_DATA) ) && (pNalUnit->nalRefIdc != 0) )
110    {
111        return(HANTRO_NOK);
112    }
113
114    return(HANTRO_OK);
115
116}
117
118