[deb_ffmpeg.git] / ffmpeg / libavcodec / vorbis_parser.c

/*
 * Copyright (c) 2012 Justin Ruggles
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * Vorbis audio parser
 *
 * Determines the duration for each packet.
 */

#include "get_bits.h"
#include "parser.h"
#include "xiph.h"
#include "vorbis_parser.h"

static int parse_id_header(AVCodecContext *avctx, VorbisParseContext *s,
                           const uint8_t *buf, int buf_size)
{
    /* Id header should be 30 bytes */
    if (buf_size < 30) {
        av_log(avctx, AV_LOG_ERROR, "Id header is too short\n");
        return AVERROR_INVALIDDATA;
    }

    /* make sure this is the Id header */
    if (buf[0] != 1) {
        av_log(avctx, AV_LOG_ERROR, "Wrong packet type in Id header\n");
        return AVERROR_INVALIDDATA;
    }

    /* check for header signature */
    if (memcmp(&buf[1], "vorbis", 6)) {
        av_log(avctx, AV_LOG_ERROR, "Invalid packet signature in Id header\n");
        return AVERROR_INVALIDDATA;
    }

    if (!(buf[29] & 0x1)) {
        av_log(avctx, AV_LOG_ERROR, "Invalid framing bit in Id header\n");
        return AVERROR_INVALIDDATA;
    }

    s->blocksize[0] = 1 << (buf[28] & 0xF);
    s->blocksize[1] = 1 << (buf[28] >>  4);

    return 0;
}

static int parse_setup_header(AVCodecContext *avctx, VorbisParseContext *s,
                              const uint8_t *buf, int buf_size)
{
    GetBitContext gb, gb0;
    uint8_t *rev_buf;
    int i, ret = 0;
    int got_framing_bit, mode_count, got_mode_header, last_mode_count = 0;

    /* avoid overread */
    if (buf_size < 7) {
        av_log(avctx, AV_LOG_ERROR, "Setup header is too short\n");
        return AVERROR_INVALIDDATA;
    }

    /* make sure this is the Setup header */
    if (buf[0] != 5) {
        av_log(avctx, AV_LOG_ERROR, "Wrong packet type in Setup header\n");
        return AVERROR_INVALIDDATA;
    }

    /* check for header signature */
    if (memcmp(&buf[1], "vorbis", 6)) {
        av_log(avctx, AV_LOG_ERROR, "Invalid packet signature in Setup header\n");
        return AVERROR_INVALIDDATA;
    }

    /* reverse bytes so we can easily read backwards with get_bits() */
    if (!(rev_buf = av_malloc(buf_size))) {
        av_log(avctx, AV_LOG_ERROR, "Out of memory\n");
        return AVERROR(ENOMEM);
    }
    for (i = 0; i < buf_size; i++)
        rev_buf[i] = buf[buf_size - 1 - i];
    init_get_bits(&gb, rev_buf, buf_size * 8);

    got_framing_bit = 0;
    while (get_bits_left(&gb) > 97) {
        if (get_bits1(&gb)) {
            got_framing_bit = get_bits_count(&gb);
            break;
        }
    }
    if (!got_framing_bit) {
        av_log(avctx, AV_LOG_ERROR, "Invalid Setup header\n");
        ret = AVERROR_INVALIDDATA;
        goto bad_header;
    }

    /* Now we search backwards to find possible valid mode counts. This is not
     * fool-proof because we could have false positive matches and read too
     * far, but there isn't really any way to be sure without parsing through
     * all the many variable-sized fields before the modes. This approach seems
     * to work well in testing, and it is similar to how it is handled in
     * liboggz. */
    mode_count = 0;
    got_mode_header = 0;
    while (get_bits_left(&gb) >= 97) {
        if (get_bits(&gb, 8) > 63 || get_bits(&gb, 16) || get_bits(&gb, 16))
            break;
        skip_bits(&gb, 1);
        mode_count++;
        if (mode_count > 64)
            break;
        gb0 = gb;
        if (get_bits(&gb0, 6) + 1 == mode_count) {
            got_mode_header = 1;
            last_mode_count = mode_count;
        }
    }
    if (!got_mode_header) {
        av_log(avctx, AV_LOG_ERROR, "Invalid Setup header\n");
        ret = AVERROR_INVALIDDATA;
        goto bad_header;
    }
    /* All samples I've seen use <= 2 modes, so ask for a sample if we find
     * more than that, as it is most likely a false positive. If we get any
     * we may need to approach this the long way and parse the whole Setup
     * header, but I hope very much that it never comes to that. */
    if (last_mode_count > 2) {
        avpriv_request_sample(avctx,
                              "%d modes (either a false positive or a "
                              "sample from an unknown encoder)",
                              last_mode_count);
    }
    /* We're limiting the mode count to 63 so that we know that the previous
     * block flag will be in the first packet byte. */
    if (last_mode_count > 63) {
        av_log(avctx, AV_LOG_ERROR, "Unsupported mode count: %d\n",
               last_mode_count);
        ret = AVERROR_INVALIDDATA;
        goto bad_header;
    }
    s->mode_count = mode_count = last_mode_count;
    /* Determine the number of bits required to code the mode and turn that
     * into a bitmask to directly access the mode from the first frame byte. */
    s->mode_mask = ((1 << (av_log2(mode_count - 1) + 1)) - 1) << 1;
    /* The previous window flag is the next bit after the mode */
    s->prev_mask = (s->mode_mask | 0x1) + 1;

    init_get_bits(&gb, rev_buf, buf_size * 8);
    skip_bits_long(&gb, got_framing_bit);
    for (i = mode_count - 1; i >= 0; i--) {
        skip_bits_long(&gb, 40);
        s->mode_blocksize[i] = get_bits1(&gb);
    }

bad_header:
    av_free(rev_buf);
    return ret;
}

int avpriv_vorbis_parse_extradata(AVCodecContext *avctx, VorbisParseContext *s)
{
    uint8_t *header_start[3];
    int header_len[3];
    int ret;

    s->avctx = avctx;
    s->extradata_parsed = 1;

    if ((ret = avpriv_split_xiph_headers(avctx->extradata,
                                         avctx->extradata_size, 30,
                                         header_start, header_len)) < 0) {
        av_log(avctx, AV_LOG_ERROR, "Extradata corrupt.\n");
        return ret;
    }

    if ((ret = parse_id_header(avctx, s, header_start[0], header_len[0])) < 0)
        return ret;

    if ((ret = parse_setup_header(avctx, s, header_start[2], header_len[2])) < 0)
        return ret;

    s->valid_extradata = 1;
    s->previous_blocksize = s->blocksize[s->mode_blocksize[0]];

    return 0;
}

int avpriv_vorbis_parse_frame_flags(VorbisParseContext *s, const uint8_t *buf,
                                    int buf_size, int *flags)
{
    int duration = 0;

    if (s->valid_extradata && buf_size > 0) {
        int mode, current_blocksize;
        int previous_blocksize = s->previous_blocksize;

        if (buf[0] & 1) {
            /* If the user doesn't care about special packets, it's a bad one. */
            if (!flags)
                goto bad_packet;

            /* Set the flag for which kind of special packet it is. */
            if (buf[0] == 1)
                *flags |= VORBIS_FLAG_HEADER;
            else if (buf[0] == 3)
                *flags |= VORBIS_FLAG_COMMENT;
            else
                goto bad_packet;

            /* Special packets have no duration. */
            return 0;

bad_packet:
            av_log(s->avctx, AV_LOG_ERROR, "Invalid packet\n");
            return AVERROR_INVALIDDATA;
        }
        if (s->mode_count == 1)
            mode = 0;
        else
            mode = (buf[0] & s->mode_mask) >> 1;
        if (mode >= s->mode_count) {
            av_log(s->avctx, AV_LOG_ERROR, "Invalid mode in packet\n");
            return AVERROR_INVALIDDATA;
        }
        if(s->mode_blocksize[mode]){
            int flag = !!(buf[0] & s->prev_mask);
            previous_blocksize = s->blocksize[flag];
        }
        current_blocksize     = s->blocksize[s->mode_blocksize[mode]];
        duration              = (previous_blocksize + current_blocksize) >> 2;
        s->previous_blocksize = current_blocksize;
    }

    return duration;
}

int avpriv_vorbis_parse_frame(VorbisParseContext *s, const uint8_t *buf,
                              int buf_size)
{
    return avpriv_vorbis_parse_frame_flags(s, buf, buf_size, NULL);
}

void avpriv_vorbis_parse_reset(VorbisParseContext *s)
{
    if (s->valid_extradata)
        s->previous_blocksize = s->blocksize[0];
}

#if CONFIG_VORBIS_PARSER
static int vorbis_parse(AVCodecParserContext *s1, AVCodecContext *avctx,
                        const uint8_t **poutbuf, int *poutbuf_size,
                        const uint8_t *buf, int buf_size)
{
    VorbisParseContext *s = s1->priv_data;
    int duration;

    if (!s->extradata_parsed && avctx->extradata && avctx->extradata_size)
        if (avpriv_vorbis_parse_extradata(avctx, s))
            goto end;

    if ((duration = avpriv_vorbis_parse_frame(s, buf, buf_size)) >= 0)
        s1->duration = duration;

end:
    /* always return the full packet. this parser isn't doing any splitting or
       combining, only packet analysis */
    *poutbuf      = buf;
    *poutbuf_size = buf_size;
    return buf_size;
}

AVCodecParser ff_vorbis_parser = {
    .codec_ids      = { AV_CODEC_ID_VORBIS },
    .priv_data_size = sizeof(VorbisParseContext),
    .parser_parse   = vorbis_parse,
};
#endif /* CONFIG_VORBIS_PARSER */
Commit	Line	Data
2ba45a60 DM	1	/*
	2	* Copyright (c) 2012 Justin Ruggles
	3	*
	4	* This file is part of FFmpeg.
	5	*
	6	* FFmpeg is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU Lesser General Public
	8	* License as published by the Free Software Foundation; either
	9	* version 2.1 of the License, or (at your option) any later version.
	10	*
	11	* FFmpeg is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	14	* Lesser General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU Lesser General Public
	17	* License along with FFmpeg; if not, write to the Free Software
	18	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	19	*/
	20
	21	/**
	22	* @file
	23	* Vorbis audio parser
	24	*
	25	* Determines the duration for each packet.
	26	*/
	27
	28	#include "get_bits.h"
	29	#include "parser.h"
	30	#include "xiph.h"
	31	#include "vorbis_parser.h"
	32
	33	static int parse_id_header(AVCodecContext avctx, VorbisParseContext s,
	34	const uint8_t *buf, int buf_size)
	35	{
	36	/* Id header should be 30 bytes */
	37	if (buf_size < 30) {
	38	av_log(avctx, AV_LOG_ERROR, "Id header is too short\n");
	39	return AVERROR_INVALIDDATA;
	40	}
	41
	42	/* make sure this is the Id header */
	43	if (buf[0] != 1) {
	44	av_log(avctx, AV_LOG_ERROR, "Wrong packet type in Id header\n");
	45	return AVERROR_INVALIDDATA;
	46	}
	47
	48	/* check for header signature */
	49	if (memcmp(&buf[1], "vorbis", 6)) {
	50	av_log(avctx, AV_LOG_ERROR, "Invalid packet signature in Id header\n");
	51	return AVERROR_INVALIDDATA;
	52	}
	53
	54	if (!(buf[29] & 0x1)) {
	55	av_log(avctx, AV_LOG_ERROR, "Invalid framing bit in Id header\n");
	56	return AVERROR_INVALIDDATA;
	57	}
	58
	59	s->blocksize[0] = 1 << (buf[28] & 0xF);
	60	s->blocksize[1] = 1 << (buf[28] >> 4);
	61
	62	return 0;
	63	}
	64
65	static int parse_setup_header(AVCodecContext avctx, VorbisParseContext s,
66	const uint8_t *buf, int buf_size)
67	{
68	GetBitContext gb, gb0;
69	uint8_t *rev_buf;
70	int i, ret = 0;
71	int got_framing_bit, mode_count, got_mode_header, last_mode_count = 0;
72
73	/* avoid overread */
74	if (buf_size < 7) {
75	av_log(avctx, AV_LOG_ERROR, "Setup header is too short\n");
76	return AVERROR_INVALIDDATA;
77	}
78
79	/* make sure this is the Setup header */
80	if (buf[0] != 5) {
81	av_log(avctx, AV_LOG_ERROR, "Wrong packet type in Setup header\n");
82	return AVERROR_INVALIDDATA;
83	}
84
85	/* check for header signature */
86	if (memcmp(&buf[1], "vorbis", 6)) {
87	av_log(avctx, AV_LOG_ERROR, "Invalid packet signature in Setup header\n");
88	return AVERROR_INVALIDDATA;
89	}
90
91	/* reverse bytes so we can easily read backwards with get_bits() */
92	if (!(rev_buf = av_malloc(buf_size))) {
93	av_log(avctx, AV_LOG_ERROR, "Out of memory\n");
94	return AVERROR(ENOMEM);
95	}
96	for (i = 0; i < buf_size; i++)
97	rev_buf[i] = buf[buf_size - 1 - i];
98	init_get_bits(&gb, rev_buf, buf_size * 8);
99
100	got_framing_bit = 0;
101	while (get_bits_left(&gb) > 97) {
102	if (get_bits1(&gb)) {
103	got_framing_bit = get_bits_count(&gb);
104	break;
105	}
106	}
107	if (!got_framing_bit) {
108	av_log(avctx, AV_LOG_ERROR, "Invalid Setup header\n");
109	ret = AVERROR_INVALIDDATA;
110	goto bad_header;
111	}
112
113	/* Now we search backwards to find possible valid mode counts. This is not
114	* fool-proof because we could have false positive matches and read too
115	* far, but there isn't really any way to be sure without parsing through
116	* all the many variable-sized fields before the modes. This approach seems
117	* to work well in testing, and it is similar to how it is handled in
118	* liboggz. */
119	mode_count = 0;
120	got_mode_header = 0;
121	while (get_bits_left(&gb) >= 97) {
122	if (get_bits(&gb, 8) > 63 \|\| get_bits(&gb, 16) \|\| get_bits(&gb, 16))
123	break;
124	skip_bits(&gb, 1);
125	mode_count++;
126	if (mode_count > 64)
127	break;
128	gb0 = gb;
129	if (get_bits(&gb0, 6) + 1 == mode_count) {
130	got_mode_header = 1;
131	last_mode_count = mode_count;
132	}
133	}
134	if (!got_mode_header) {
135	av_log(avctx, AV_LOG_ERROR, "Invalid Setup header\n");
136	ret = AVERROR_INVALIDDATA;
137	goto bad_header;
138	}
139	/* All samples I've seen use <= 2 modes, so ask for a sample if we find
140	* more than that, as it is most likely a false positive. If we get any
141	* we may need to approach this the long way and parse the whole Setup
142	* header, but I hope very much that it never comes to that. */
143	if (last_mode_count > 2) {
144	avpriv_request_sample(avctx,
145	"%d modes (either a false positive or a "
146	"sample from an unknown encoder)",
147	last_mode_count);
148	}
149	/* We're limiting the mode count to 63 so that we know that the previous
150	* block flag will be in the first packet byte. */
151	if (last_mode_count > 63) {
152	av_log(avctx, AV_LOG_ERROR, "Unsupported mode count: %d\n",
153	last_mode_count);
154	ret = AVERROR_INVALIDDATA;
155	goto bad_header;
156	}
157	s->mode_count = mode_count = last_mode_count;
158	/* Determine the number of bits required to code the mode and turn that
159	* into a bitmask to directly access the mode from the first frame byte. */
160	s->mode_mask = ((1 << (av_log2(mode_count - 1) + 1)) - 1) << 1;
161	/* The previous window flag is the next bit after the mode */
162	s->prev_mask = (s->mode_mask \| 0x1) + 1;
163
164	init_get_bits(&gb, rev_buf, buf_size * 8);
165	skip_bits_long(&gb, got_framing_bit);
166	for (i = mode_count - 1; i >= 0; i--) {
167	skip_bits_long(&gb, 40);
168	s->mode_blocksize[i] = get_bits1(&gb);
169	}
170
171	bad_header:
172	av_free(rev_buf);
173	return ret;
174	}
175
176	int avpriv_vorbis_parse_extradata(AVCodecContext avctx, VorbisParseContext s)
177	{
178	uint8_t *header_start[3];
179	int header_len[3];
180	int ret;
181
182	s->avctx = avctx;
183	s->extradata_parsed = 1;
184
185	if ((ret = avpriv_split_xiph_headers(avctx->extradata,
186	avctx->extradata_size, 30,
187	header_start, header_len)) < 0) {
188	av_log(avctx, AV_LOG_ERROR, "Extradata corrupt.\n");
189	return ret;
190	}
191
192	if ((ret = parse_id_header(avctx, s, header_start[0], header_len[0])) < 0)
193	return ret;
194
195	if ((ret = parse_setup_header(avctx, s, header_start[2], header_len[2])) < 0)
196	return ret;
197
198	s->valid_extradata = 1;
199	s->previous_blocksize = s->blocksize[s->mode_blocksize[0]];
200
201	return 0;
202	}
203
204	int avpriv_vorbis_parse_frame_flags(VorbisParseContext s, const uint8_t buf,
205	int buf_size, int *flags)
206	{
207	int duration = 0;
208
209	if (s->valid_extradata && buf_size > 0) {
210	int mode, current_blocksize;
211	int previous_blocksize = s->previous_blocksize;
212
213	if (buf[0] & 1) {
214	/* If the user doesn't care about special packets, it's a bad one. */
215	if (!flags)
216	goto bad_packet;
217
218	/* Set the flag for which kind of special packet it is. */
219	if (buf[0] == 1)
220	*flags \|= VORBIS_FLAG_HEADER;
221	else if (buf[0] == 3)
222	*flags \|= VORBIS_FLAG_COMMENT;
223	else
224	goto bad_packet;
225
226	/* Special packets have no duration. */
227	return 0;
228
229	bad_packet:
230	av_log(s->avctx, AV_LOG_ERROR, "Invalid packet\n");
231	return AVERROR_INVALIDDATA;
232	}
233	if (s->mode_count == 1)
234	mode = 0;
235	else
236	mode = (buf[0] & s->mode_mask) >> 1;
237	if (mode >= s->mode_count) {
238	av_log(s->avctx, AV_LOG_ERROR, "Invalid mode in packet\n");
239	return AVERROR_INVALIDDATA;
240	}
241	if(s->mode_blocksize[mode]){
242	int flag = !!(buf[0] & s->prev_mask);
243	previous_blocksize = s->blocksize[flag];
244	}
245	current_blocksize = s->blocksize[s->mode_blocksize[mode]];
246	duration = (previous_blocksize + current_blocksize) >> 2;
247	s->previous_blocksize = current_blocksize;
248	}
249
250	return duration;
251	}
252
253	int avpriv_vorbis_parse_frame(VorbisParseContext s, const uint8_t buf,
254	int buf_size)
255	{
256	return avpriv_vorbis_parse_frame_flags(s, buf, buf_size, NULL);
257	}
258
259	void avpriv_vorbis_parse_reset(VorbisParseContext *s)
260	{
261	if (s->valid_extradata)
262	s->previous_blocksize = s->blocksize[0];
263	}
264
265	#if CONFIG_VORBIS_PARSER
266	static int vorbis_parse(AVCodecParserContext s1, AVCodecContext avctx,
267	const uint8_t *poutbuf, int poutbuf_size,
268	const uint8_t *buf, int buf_size)
269	{
270	VorbisParseContext *s = s1->priv_data;
271	int duration;
272
273	if (!s->extradata_parsed && avctx->extradata && avctx->extradata_size)
274	if (avpriv_vorbis_parse_extradata(avctx, s))
275	goto end;
276
277	if ((duration = avpriv_vorbis_parse_frame(s, buf, buf_size)) >= 0)
278	s1->duration = duration;
279
280	end:
281	/* always return the full packet. this parser isn't doing any splitting or
282	combining, only packet analysis */
283	*poutbuf = buf;
284	*poutbuf_size = buf_size;
285	return buf_size;
286	}
287
288	AVCodecParser ff_vorbis_parser = {
289	.codec_ids = { AV_CODEC_ID_VORBIS },
290	.priv_data_size = sizeof(VorbisParseContext),
291	.parser_parse = vorbis_parse,
292	};
293	#endif /* CONFIG_VORBIS_PARSER */