1 /*
2 * RAW H.264 video demuxer
3 * Copyright (c) 2008 Michael Niedermayer <michaelni@gmx.at>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 #include "libavcodec/get_bits.h"
23 #include "libavcodec/golomb.h"
24 #include "avformat.h"
25 #include "rawdec.h"
26 #include "libavcodec/internal.h"
27
28 #define MAX_SPS_COUNT 32
29 #define MAX_PPS_COUNT 256
30
h264_probe(const AVProbeData * p)31 static int h264_probe(const AVProbeData *p)
32 {
33 uint32_t code = -1;
34 int sps = 0, pps = 0, idr = 0, res = 0, sli = 0;
35 int i, ret;
36 int pps_ids[MAX_PPS_COUNT+1] = {0};
37 int sps_ids[MAX_SPS_COUNT+1] = {0};
38 unsigned pps_id, sps_id;
39 GetBitContext gb;
40
41 for (i = 0; i + 2 < p->buf_size; i++) {
42 code = (code << 8) + p->buf[i];
43 if ((code & 0xffffff00) == 0x100) {
44 int ref_idc = (code >> 5) & 3;
45 int type = code & 0x1F;
46 static const int8_t ref_zero[] = {
47 2, 0, 0, 0, 0, -1, 1, -1,
48 -1, 1, 1, 1, 1, -1, 2, 2,
49 2, 2, 2, 0, 2, 2, 2, 2,
50 2, 2, 2, 2, 2, 2, 2, 2
51 };
52
53 if (code & 0x80) // forbidden_bit
54 return 0;
55
56 if (ref_zero[type] == 1 && ref_idc)
57 return 0;
58 if (ref_zero[type] == -1 && !ref_idc)
59 return 0;
60 if (ref_zero[type] == 2) {
61 if (!(code == 0x100 && !p->buf[i + 1] && !p->buf[i + 2]))
62 res++;
63 }
64
65 ret = init_get_bits8(&gb, p->buf + i + 1, p->buf_size - i - 1);
66 if (ret < 0)
67 return 0;
68
69 switch (type) {
70 case 1:
71 case 5:
72 get_ue_golomb_long(&gb);
73 if (get_ue_golomb_long(&gb) > 9U)
74 return 0;
75 pps_id = get_ue_golomb_long(&gb);
76 if (pps_id > MAX_PPS_COUNT)
77 return 0;
78 if (!pps_ids[pps_id])
79 break;
80
81 if (type == 1)
82 sli++;
83 else
84 idr++;
85 break;
86 case 7:
87 skip_bits(&gb, 14);
88 if (get_bits(&gb, 2))
89 return 0;
90 skip_bits(&gb, 8);
91 sps_id = get_ue_golomb_long(&gb);
92 if (sps_id > MAX_SPS_COUNT)
93 return 0;
94 sps_ids[sps_id] = 1;
95 sps++;
96 break;
97 case 8:
98 pps_id = get_ue_golomb_long(&gb);
99 if (pps_id > MAX_PPS_COUNT)
100 return 0;
101 sps_id = get_ue_golomb_long(&gb);
102 if (sps_id > MAX_SPS_COUNT)
103 return 0;
104 if (!sps_ids[sps_id])
105 break;
106 pps_ids[pps_id] = 1;
107 pps++;
108 break;
109 }
110 }
111 }
112 ff_tlog(NULL, "sps:%d pps:%d idr:%d sli:%d res:%d\n", sps, pps, idr, sli, res);
113
114 if (sps && pps && (idr || sli > 3) && res < (sps + pps + idr))
115 return AVPROBE_SCORE_EXTENSION + 1; // 1 more than .mpg
116
117 return 0;
118 }
119
120 FF_DEF_RAWVIDEO_DEMUXER(h264, "raw H.264 video", h264_probe, "h26l,h264,264,avc", AV_CODEC_ID_H264)
121