GCC Code Coverage Report
Directory: ../../../ffmpeg/ Exec Total Coverage
File: src/libavcodec/vorbis_parser.c Lines: 102 154 66.2 %
Date: 2020-08-11 16:46:18 Branches: 47 86 54.7 %

Line Branch Exec Source
1
/*
2
 * Copyright (c) 2012 Justin Ruggles
3
 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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/**
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 * @file
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 * Vorbis audio parser
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 *
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 * Determines the duration for each packet.
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 */
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28
#include "libavutil/log.h"
29
30
#include "get_bits.h"
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#include "parser.h"
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#include "xiph.h"
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#include "vorbis_parser_internal.h"
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35
static const AVClass vorbis_parser_class = {
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    .class_name = "Vorbis parser",
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    .item_name  = av_default_item_name,
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    .version    = LIBAVUTIL_VERSION_INT,
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};
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41
37
static int parse_id_header(AVVorbisParseContext *s,
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                           const uint8_t *buf, int buf_size)
43
{
44
    /* Id header should be 30 bytes */
45
37
    if (buf_size < 30) {
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        av_log(s, AV_LOG_ERROR, "Id header is too short\n");
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        return AVERROR_INVALIDDATA;
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    }
49
50
    /* make sure this is the Id header */
51
37
    if (buf[0] != 1) {
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        av_log(s, AV_LOG_ERROR, "Wrong packet type in Id header\n");
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        return AVERROR_INVALIDDATA;
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    }
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56
    /* check for header signature */
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37
    if (memcmp(&buf[1], "vorbis", 6)) {
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        av_log(s, AV_LOG_ERROR, "Invalid packet signature in Id header\n");
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        return AVERROR_INVALIDDATA;
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    }
61
62
37
    if (!(buf[29] & 0x1)) {
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        av_log(s, AV_LOG_ERROR, "Invalid framing bit in Id header\n");
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        return AVERROR_INVALIDDATA;
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    }
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67
37
    s->blocksize[0] = 1 << (buf[28] & 0xF);
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37
    s->blocksize[1] = 1 << (buf[28] >>  4);
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70
37
    return 0;
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}
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73
37
static int parse_setup_header(AVVorbisParseContext *s,
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                              const uint8_t *buf, int buf_size)
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{
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    GetBitContext gb, gb0;
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    uint8_t *rev_buf;
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37
    int i, ret = 0;
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37
    int got_framing_bit, mode_count, got_mode_header, last_mode_count = 0;
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81
    /* avoid overread */
82
37
    if (buf_size < 7) {
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        av_log(s, AV_LOG_ERROR, "Setup header is too short\n");
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        return AVERROR_INVALIDDATA;
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    }
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87
    /* make sure this is the Setup header */
88
37
    if (buf[0] != 5) {
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        av_log(s, AV_LOG_ERROR, "Wrong packet type in Setup header\n");
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        return AVERROR_INVALIDDATA;
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    }
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    /* check for header signature */
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37
    if (memcmp(&buf[1], "vorbis", 6)) {
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        av_log(s, AV_LOG_ERROR, "Invalid packet signature in Setup header\n");
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        return AVERROR_INVALIDDATA;
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    }
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99
    /* reverse bytes so we can easily read backwards with get_bits() */
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37
    if (!(rev_buf = av_malloc(buf_size))) {
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        av_log(s, AV_LOG_ERROR, "Out of memory\n");
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        return AVERROR(ENOMEM);
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    }
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193316
    for (i = 0; i < buf_size; i++)
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193279
        rev_buf[i] = buf[buf_size - 1 - i];
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37
    init_get_bits(&gb, rev_buf, buf_size * 8);
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108
37
    got_framing_bit = 0;
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181
    while (get_bits_left(&gb) > 97) {
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181
        if (get_bits1(&gb)) {
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37
            got_framing_bit = get_bits_count(&gb);
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37
            break;
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        }
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    }
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37
    if (!got_framing_bit) {
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        av_log(s, AV_LOG_ERROR, "Invalid Setup header\n");
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        ret = AVERROR_INVALIDDATA;
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        goto bad_header;
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    }
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121
    /* Now we search backwards to find possible valid mode counts. This is not
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     * fool-proof because we could have false positive matches and read too
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     * far, but there isn't really any way to be sure without parsing through
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     * all the many variable-sized fields before the modes. This approach seems
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     * to work well in testing, and it is similar to how it is handled in
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     * liboggz. */
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37
    mode_count = 0;
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37
    got_mode_header = 0;
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111
    while (get_bits_left(&gb) >= 97) {
130

111
        if (get_bits(&gb, 8) > 63 || get_bits(&gb, 16) || get_bits(&gb, 16))
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            break;
132
74
        skip_bits(&gb, 1);
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74
        mode_count++;
134
74
        if (mode_count > 64)
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            break;
136
74
        gb0 = gb;
137
74
        if (get_bits(&gb0, 6) + 1 == mode_count) {
138
74
            got_mode_header = 1;
139
74
            last_mode_count = mode_count;
140
        }
141
    }
142
37
    if (!got_mode_header) {
143
        av_log(s, AV_LOG_ERROR, "Invalid Setup header\n");
144
        ret = AVERROR_INVALIDDATA;
145
        goto bad_header;
146
    }
147
    /* All samples I've seen use <= 2 modes, so ask for a sample if we find
148
     * more than that, as it is most likely a false positive. If we get any
149
     * we may need to approach this the long way and parse the whole Setup
150
     * header, but I hope very much that it never comes to that. */
151
37
    if (last_mode_count > 2) {
152
        avpriv_request_sample(s,
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                              "%d modes (either a false positive or a "
154
                              "sample from an unknown encoder)",
155
                              last_mode_count);
156
    }
157
    /* We're limiting the mode count to 63 so that we know that the previous
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     * block flag will be in the first packet byte. */
159
37
    if (last_mode_count > 63) {
160
        av_log(s, AV_LOG_ERROR, "Unsupported mode count: %d\n",
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               last_mode_count);
162
        ret = AVERROR_INVALIDDATA;
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        goto bad_header;
164
    }
165
37
    s->mode_count = mode_count = last_mode_count;
166
    /* Determine the number of bits required to code the mode and turn that
167
     * into a bitmask to directly access the mode from the first frame byte. */
168
37
    s->mode_mask = ((1 << (av_log2(mode_count - 1) + 1)) - 1) << 1;
169
    /* The previous window flag is the next bit after the mode */
170
37
    s->prev_mask = (s->mode_mask | 0x1) + 1;
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172
37
    init_get_bits(&gb, rev_buf, buf_size * 8);
173
37
    skip_bits_long(&gb, got_framing_bit);
174
111
    for (i = mode_count - 1; i >= 0; i--) {
175
74
        skip_bits_long(&gb, 40);
176
74
        s->mode_blocksize[i] = get_bits1(&gb);
177
    }
178
179
37
bad_header:
180
37
    av_free(rev_buf);
181
37
    return ret;
182
}
183
184
37
static int vorbis_parse_init(AVVorbisParseContext *s,
185
                             const uint8_t *extradata, int extradata_size)
186
{
187
    const uint8_t *header_start[3];
188
    int header_len[3];
189
    int ret;
190
191
37
    s->class = &vorbis_parser_class;
192
37
    s->extradata_parsed = 1;
193
194
37
    if ((ret = avpriv_split_xiph_headers(extradata,
195
                                         extradata_size, 30,
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                                         header_start, header_len)) < 0) {
197
        av_log(s, AV_LOG_ERROR, "Extradata corrupt.\n");
198
        return ret;
199
    }
200
201
37
    if ((ret = parse_id_header(s, header_start[0], header_len[0])) < 0)
202
        return ret;
203
204
37
    if ((ret = parse_setup_header(s, header_start[2], header_len[2])) < 0)
205
        return ret;
206
207
37
    s->valid_extradata = 1;
208
37
    s->previous_blocksize = s->blocksize[s->mode_blocksize[0]];
209
210
37
    return 0;
211
}
212
213
153725
int av_vorbis_parse_frame_flags(AVVorbisParseContext *s, const uint8_t *buf,
214
                                int buf_size, int *flags)
215
{
216
153725
    int duration = 0;
217
218

153725
    if (s->valid_extradata && buf_size > 0) {
219
        int mode, current_blocksize;
220
153716
        int previous_blocksize = s->previous_blocksize;
221
222
153716
        if (buf[0] & 1) {
223
            /* If the user doesn't care about special packets, it's a bad one. */
224
            if (!flags)
225
                goto bad_packet;
226
227
            /* Set the flag for which kind of special packet it is. */
228
            if (buf[0] == 1)
229
                *flags |= VORBIS_FLAG_HEADER;
230
            else if (buf[0] == 3)
231
                *flags |= VORBIS_FLAG_COMMENT;
232
            else if (buf[0] == 5)
233
                *flags |= VORBIS_FLAG_SETUP;
234
            else
235
                goto bad_packet;
236
237
            /* Special packets have no duration. */
238
            return 0;
239
240
bad_packet:
241
            av_log(s, AV_LOG_ERROR, "Invalid packet\n");
242
            return AVERROR_INVALIDDATA;
243
        }
244
153716
        if (s->mode_count == 1)
245
            mode = 0;
246
        else
247
153716
            mode = (buf[0] & s->mode_mask) >> 1;
248
153716
        if (mode >= s->mode_count) {
249
            av_log(s, AV_LOG_ERROR, "Invalid mode in packet\n");
250
            return AVERROR_INVALIDDATA;
251
        }
252
153716
        if(s->mode_blocksize[mode]){
253
85650
            int flag = !!(buf[0] & s->prev_mask);
254
85650
            previous_blocksize = s->blocksize[flag];
255
        }
256
153716
        current_blocksize     = s->blocksize[s->mode_blocksize[mode]];
257
153716
        duration              = (previous_blocksize + current_blocksize) >> 2;
258
153716
        s->previous_blocksize = current_blocksize;
259
    }
260
261
153725
    return duration;
262
}
263
264
579
int av_vorbis_parse_frame(AVVorbisParseContext *s, const uint8_t *buf,
265
                          int buf_size)
266
{
267
579
    return av_vorbis_parse_frame_flags(s, buf, buf_size, NULL);
268
}
269
270
19264
void av_vorbis_parse_reset(AVVorbisParseContext *s)
271
{
272
19264
    if (s->valid_extradata)
273
19264
        s->previous_blocksize = s->blocksize[0];
274
19264
}
275
276
64
void av_vorbis_parse_free(AVVorbisParseContext **s)
277
{
278
64
    av_freep(s);
279
64
}
280
281
37
AVVorbisParseContext *av_vorbis_parse_init(const uint8_t *extradata,
282
                                           int extradata_size)
283
{
284
37
    AVVorbisParseContext *s = av_mallocz(sizeof(*s));
285
    int ret;
286
287
37
    if (!s)
288
        return NULL;
289
290
37
    ret = vorbis_parse_init(s, extradata, extradata_size);
291
37
    if (ret < 0) {
292
        av_vorbis_parse_free(&s);
293
        return NULL;
294
    }
295
296
37
    return s;
297
}
298
299
#if CONFIG_VORBIS_PARSER
300
301
typedef struct VorbisParseContext {
302
    AVVorbisParseContext *vp;
303
} VorbisParseContext;
304
305
579
static int vorbis_parse(AVCodecParserContext *s1, AVCodecContext *avctx,
306
                        const uint8_t **poutbuf, int *poutbuf_size,
307
                        const uint8_t *buf, int buf_size)
308
{
309
579
    VorbisParseContext *s = s1->priv_data;
310
    int duration;
311
312

579
    if (!s->vp && avctx->extradata && avctx->extradata_size) {
313
11
        s->vp = av_vorbis_parse_init(avctx->extradata, avctx->extradata_size);
314
    }
315
579
    if (!s->vp)
316
        goto end;
317
318
579
    if ((duration = av_vorbis_parse_frame(s->vp, buf, buf_size)) >= 0)
319
579
        s1->duration = duration;
320
321
end:
322
    /* always return the full packet. this parser isn't doing any splitting or
323
       combining, only packet analysis */
324
579
    *poutbuf      = buf;
325
579
    *poutbuf_size = buf_size;
326
579
    return buf_size;
327
}
328
329
38
static void vorbis_parser_close(AVCodecParserContext *ctx)
330
{
331
38
    VorbisParseContext *s = ctx->priv_data;
332
38
    av_vorbis_parse_free(&s->vp);
333
38
}
334
335
AVCodecParser ff_vorbis_parser = {
336
    .codec_ids      = { AV_CODEC_ID_VORBIS },
337
    .priv_data_size = sizeof(VorbisParseContext),
338
    .parser_parse   = vorbis_parse,
339
    .parser_close   = vorbis_parser_close,
340
};
341
#endif /* CONFIG_VORBIS_PARSER */