341 lines
10 KiB
C
Executable file
341 lines
10 KiB
C
Executable file
/*
|
|
* 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 "libavutil/log.h"
|
|
|
|
#include "get_bits.h"
|
|
#include "parser.h"
|
|
#include "xiph.h"
|
|
#include "vorbis_parser_internal.h"
|
|
|
|
static const AVClass vorbis_parser_class = {
|
|
.class_name = "Vorbis parser",
|
|
.item_name = av_default_item_name,
|
|
.version = LIBAVUTIL_VERSION_INT,
|
|
};
|
|
|
|
static int parse_id_header(AVVorbisParseContext *s,
|
|
const uint8_t *buf, int buf_size)
|
|
{
|
|
/* Id header should be 30 bytes */
|
|
if (buf_size < 30) {
|
|
av_log(s, 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(s, 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(s, AV_LOG_ERROR, "Invalid packet signature in Id header\n");
|
|
return AVERROR_INVALIDDATA;
|
|
}
|
|
|
|
if (!(buf[29] & 0x1)) {
|
|
av_log(s, 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(AVVorbisParseContext *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(s, 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(s, 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(s, 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(s, 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(s, 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(s, 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(s,
|
|
"%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(s, 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;
|
|
}
|
|
|
|
static int vorbis_parse_init(AVVorbisParseContext *s,
|
|
const uint8_t *extradata, int extradata_size)
|
|
{
|
|
const uint8_t *header_start[3];
|
|
int header_len[3];
|
|
int ret;
|
|
|
|
s->class = &vorbis_parser_class;
|
|
s->extradata_parsed = 1;
|
|
|
|
if ((ret = avpriv_split_xiph_headers(extradata,
|
|
extradata_size, 30,
|
|
header_start, header_len)) < 0) {
|
|
av_log(s, AV_LOG_ERROR, "Extradata corrupt.\n");
|
|
return ret;
|
|
}
|
|
|
|
if ((ret = parse_id_header(s, header_start[0], header_len[0])) < 0)
|
|
return ret;
|
|
|
|
if ((ret = parse_setup_header(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 av_vorbis_parse_frame_flags(AVVorbisParseContext *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 if (buf[0] == 5)
|
|
*flags |= VORBIS_FLAG_SETUP;
|
|
else
|
|
goto bad_packet;
|
|
|
|
/* Special packets have no duration. */
|
|
return 0;
|
|
|
|
bad_packet:
|
|
av_log(s, 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, 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 av_vorbis_parse_frame(AVVorbisParseContext *s, const uint8_t *buf,
|
|
int buf_size)
|
|
{
|
|
return av_vorbis_parse_frame_flags(s, buf, buf_size, NULL);
|
|
}
|
|
|
|
void av_vorbis_parse_reset(AVVorbisParseContext *s)
|
|
{
|
|
if (s->valid_extradata)
|
|
s->previous_blocksize = s->blocksize[0];
|
|
}
|
|
|
|
void av_vorbis_parse_free(AVVorbisParseContext **s)
|
|
{
|
|
av_freep(s);
|
|
}
|
|
|
|
AVVorbisParseContext *av_vorbis_parse_init(const uint8_t *extradata,
|
|
int extradata_size)
|
|
{
|
|
AVVorbisParseContext *s = av_mallocz(sizeof(*s));
|
|
int ret;
|
|
|
|
if (!s)
|
|
return NULL;
|
|
|
|
ret = vorbis_parse_init(s, extradata, extradata_size);
|
|
if (ret < 0) {
|
|
av_vorbis_parse_free(&s);
|
|
return NULL;
|
|
}
|
|
|
|
return s;
|
|
}
|
|
|
|
#if CONFIG_VORBIS_PARSER
|
|
|
|
typedef struct VorbisParseContext {
|
|
AVVorbisParseContext *vp;
|
|
} VorbisParseContext;
|
|
|
|
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->vp && avctx->extradata && avctx->extradata_size) {
|
|
s->vp = av_vorbis_parse_init(avctx->extradata, avctx->extradata_size);
|
|
}
|
|
if (!s->vp)
|
|
goto end;
|
|
|
|
if ((duration = av_vorbis_parse_frame(s->vp, 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;
|
|
}
|
|
|
|
static void vorbis_parser_close(AVCodecParserContext *ctx)
|
|
{
|
|
VorbisParseContext *s = ctx->priv_data;
|
|
av_vorbis_parse_free(&s->vp);
|
|
}
|
|
|
|
AVCodecParser ff_vorbis_parser = {
|
|
.codec_ids = { AV_CODEC_ID_VORBIS },
|
|
.priv_data_size = sizeof(VorbisParseContext),
|
|
.parser_parse = vorbis_parse,
|
|
.parser_close = vorbis_parser_close,
|
|
};
|
|
#endif /* CONFIG_VORBIS_PARSER */
|