Statistics
| Branch: | Revision:

ffmpeg / libavcodec / h264_mp4toannexb_bsf.c @ 4e84f994

History | View | Annotate | Download (6.21 KB)

1
/*
2
 * H.264 MP4 to Annex B byte stream format filter
3
 * Copyright (c) 2007 Benoit Fouet <benoit.fouet@free.fr>
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 "libavutil/intreadwrite.h"
23
#include "avcodec.h"
24

    
25
typedef struct H264BSFContext {
26
    uint8_t  length_size;
27
    uint8_t  first_idr;
28
    int      extradata_parsed;
29
} H264BSFContext;
30

    
31
static int alloc_and_copy(uint8_t **poutbuf,          int *poutbuf_size,
32
                          const uint8_t *sps_pps, uint32_t sps_pps_size,
33
                          const uint8_t *in,      uint32_t in_size) {
34
    uint32_t offset = *poutbuf_size;
35
    uint8_t nal_header_size = offset ? 3 : 4;
36
    void *tmp;
37

    
38
    *poutbuf_size += sps_pps_size+in_size+nal_header_size;
39
    tmp = av_realloc(*poutbuf, *poutbuf_size);
40
    if (!tmp)
41
        return AVERROR(ENOMEM);
42
    *poutbuf = tmp;
43
    if (sps_pps)
44
        memcpy(*poutbuf+offset, sps_pps, sps_pps_size);
45
    memcpy(*poutbuf+sps_pps_size+nal_header_size+offset, in, in_size);
46
    if (!offset) {
47
        AV_WB32(*poutbuf+sps_pps_size, 1);
48
    } else {
49
        (*poutbuf+offset+sps_pps_size)[0] = (*poutbuf+offset+sps_pps_size)[1] = 0;
50
        (*poutbuf+offset+sps_pps_size)[2] = 1;
51
    }
52

    
53
    return 0;
54
}
55

    
56
static int h264_mp4toannexb_filter(AVBitStreamFilterContext *bsfc,
57
                                   AVCodecContext *avctx, const char *args,
58
                                   uint8_t  **poutbuf, int *poutbuf_size,
59
                                   const uint8_t *buf, int      buf_size,
60
                                   int keyframe) {
61
    H264BSFContext *ctx = bsfc->priv_data;
62
    uint8_t unit_type;
63
    int32_t nal_size;
64
    uint32_t cumul_size = 0;
65
    const uint8_t *buf_end = buf + buf_size;
66

    
67
    /* nothing to filter */
68
    if (!avctx->extradata || avctx->extradata_size < 6) {
69
        *poutbuf = (uint8_t*) buf;
70
        *poutbuf_size = buf_size;
71
        return 0;
72
    }
73

    
74
    /* retrieve sps and pps NAL units from extradata */
75
    if (!ctx->extradata_parsed) {
76
        uint16_t unit_size;
77
        uint64_t total_size = 0;
78
        uint8_t *out = NULL, unit_nb, sps_done = 0, sps_seen = 0, pps_seen = 0;
79
        const uint8_t *extradata = avctx->extradata+4;
80
        static const uint8_t nalu_header[4] = {0, 0, 0, 1};
81

    
82
        /* retrieve length coded size */
83
        ctx->length_size = (*extradata++ & 0x3) + 1;
84
        if (ctx->length_size == 3)
85
            return AVERROR(EINVAL);
86

    
87
        /* retrieve sps and pps unit(s) */
88
        unit_nb = *extradata++ & 0x1f; /* number of sps unit(s) */
89
        if (!unit_nb) {
90
            unit_nb = *extradata++; /* number of pps unit(s) */
91
            sps_done++;
92

    
93
            if (unit_nb)
94
                pps_seen = 1;
95
        } else {
96
            sps_seen = 1;
97
        }
98

    
99
        while (unit_nb--) {
100
            void *tmp;
101

    
102
            unit_size = AV_RB16(extradata);
103
            total_size += unit_size+4;
104
            if (total_size > INT_MAX - FF_INPUT_BUFFER_PADDING_SIZE ||
105
                extradata+2+unit_size > avctx->extradata+avctx->extradata_size) {
106
                av_free(out);
107
                return AVERROR(EINVAL);
108
            }
109
            tmp = av_realloc(out, total_size + FF_INPUT_BUFFER_PADDING_SIZE);
110
            if (!tmp) {
111
                av_free(out);
112
                return AVERROR(ENOMEM);
113
            }
114
            out = tmp;
115
            memcpy(out+total_size-unit_size-4, nalu_header, 4);
116
            memcpy(out+total_size-unit_size,   extradata+2, unit_size);
117
            extradata += 2+unit_size;
118

    
119
            if (!unit_nb && !sps_done++)
120
                unit_nb = *extradata++; /* number of pps unit(s) */
121
        }
122

    
123
        if(out)
124
            memset(out + total_size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
125

    
126
        if (!sps_seen)
127
            av_log(avctx, AV_LOG_WARNING, "Warning: SPS NALU missing or invalid. The resulting stream may not play.\n");
128
        if (!pps_seen)
129
            av_log(avctx, AV_LOG_WARNING, "Warning: PPS NALU missing or invalid. The resulting stream may not play.\n");
130

    
131
        av_free(avctx->extradata);
132
        avctx->extradata      = out;
133
        avctx->extradata_size = total_size;
134
        ctx->first_idr        = 1;
135
        ctx->extradata_parsed = 1;
136
    }
137

    
138
    *poutbuf_size = 0;
139
    *poutbuf = NULL;
140
    do {
141
        if (buf + ctx->length_size > buf_end)
142
            goto fail;
143

    
144
        if (ctx->length_size == 1) {
145
            nal_size = buf[0];
146
        } else if (ctx->length_size == 2) {
147
            nal_size = AV_RB16(buf);
148
        } else
149
            nal_size = AV_RB32(buf);
150

    
151
        buf += ctx->length_size;
152
        unit_type = *buf & 0x1f;
153

    
154
        if (buf + nal_size > buf_end || nal_size < 0)
155
            goto fail;
156

    
157
        /* prepend only to the first type 5 NAL unit of an IDR picture */
158
        if (ctx->first_idr && unit_type == 5) {
159
            if (alloc_and_copy(poutbuf, poutbuf_size,
160
                               avctx->extradata, avctx->extradata_size,
161
                               buf, nal_size) < 0)
162
                goto fail;
163
            ctx->first_idr = 0;
164
        } else {
165
            if (alloc_and_copy(poutbuf, poutbuf_size,
166
                               NULL, 0,
167
                               buf, nal_size) < 0)
168
                goto fail;
169
            if (!ctx->first_idr && unit_type == 1)
170
                ctx->first_idr = 1;
171
        }
172

    
173
        buf += nal_size;
174
        cumul_size += nal_size + ctx->length_size;
175
    } while (cumul_size < buf_size);
176

    
177
    return 1;
178

    
179
fail:
180
    av_freep(poutbuf);
181
    *poutbuf_size = 0;
182
    return AVERROR(EINVAL);
183
}
184

    
185
AVBitStreamFilter ff_h264_mp4toannexb_bsf = {
186
    "h264_mp4toannexb",
187
    sizeof(H264BSFContext),
188
    h264_mp4toannexb_filter,
189
};
190