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
27 #define MAX_SPS_COUNT 32
28 #define MAX_PPS_COUNT 256
29
h264_probe(const AVProbeData *p)30 static int h264_probe(const AVProbeData *p)
31 {
32 uint32_t code = -1;
33 int sps = 0, pps = 0, idr = 0, res = 0, sli = 0;
34 int i, ret;
35 int pps_ids[MAX_PPS_COUNT+1] = {0};
36 int sps_ids[MAX_SPS_COUNT+1] = {0};
37 unsigned pps_id, sps_id;
38 GetBitContext gb;
39
40 for (i = 0; i + 2 < p->buf_size; i++) {
41 code = (code << 8) + p->buf[i];
42 if ((code & 0xffffff00) == 0x100) {
43 int ref_idc = (code >> 5) & 3;
44 int type = code & 0x1F;
45 static const int8_t ref_zero[] = {
46 2, 0, 0, 0, 0, -1, 1, -1,
47 -1, 1, 1, 1, 1, -1, 2, 2,
48 2, 2, 2, 0, 2, 2, 2, 2,
49 2, 2, 2, 2, 2, 2, 2, 2
50 };
51
52 if (code & 0x80) // forbidden_bit
53 return 0;
54
55 if (ref_zero[type] == 1 && ref_idc)
56 return 0;
57 if (ref_zero[type] == -1 && !ref_idc)
58 return 0;
59 if (ref_zero[type] == 2) {
60 if (!(code == 0x100 && !p->buf[i + 1] && !p->buf[i + 2]))
61 res++;
62 }
63
64 ret = init_get_bits8(&gb, p->buf + i + 1, p->buf_size - i - 1);
65 if (ret < 0)
66 return 0;
67
68 switch (type) {
69 case 1:
70 case 5:
71 get_ue_golomb_long(&gb);
72 if (get_ue_golomb_long(&gb) > 9U)
73 return 0;
74 pps_id = get_ue_golomb_long(&gb);
75 if (pps_id > MAX_PPS_COUNT)
76 return 0;
77 if (!pps_ids[pps_id])
78 break;
79
80 if (type == 1)
81 sli++;
82 else
83 idr++;
84 break;
85 case 7:
86 skip_bits(&gb, 14);
87 if (get_bits(&gb, 2))
88 return 0;
89 skip_bits(&gb, 8);
90 sps_id = get_ue_golomb_long(&gb);
91 if (sps_id > MAX_SPS_COUNT)
92 return 0;
93 sps_ids[sps_id] = 1;
94 sps++;
95 break;
96 case 8:
97 pps_id = get_ue_golomb_long(&gb);
98 if (pps_id > MAX_PPS_COUNT)
99 return 0;
100 sps_id = get_ue_golomb_long(&gb);
101 if (sps_id > MAX_SPS_COUNT)
102 return 0;
103 if (!sps_ids[sps_id])
104 break;
105 pps_ids[pps_id] = 1;
106 pps++;
107 break;
108 }
109 }
110 }
111 ff_tlog(NULL, "sps:%d pps:%d idr:%d sli:%d res:%d\n", sps, pps, idr, sli, res);
112
113 if (sps && pps && (idr || sli > 3) && res < (sps + pps + idr))
114 return AVPROBE_SCORE_EXTENSION + 1; // 1 more than .mpg
115
116 return 0;
117 }
118
119 FF_DEF_RAWVIDEO_DEMUXER(h264, "raw H.264 video", h264_probe, "h26l,h264,264,avc", AV_CODEC_ID_H264)
120