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mp3dec: decode more data from Info header

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Signed-off-by: Anton Khirnov <anton@khirnov.net>
This commit is contained in:
Alessandro Ghedini 2014-04-13 14:23:57 +02:00 committed by Anton Khirnov
parent 0983d48111
commit 32d05934ab
3 changed files with 101 additions and 10 deletions
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2
libavformat/avio_internal.h
View File

@ -94,6 +94,8 @@ void ffio_init_checksum(AVIOContext *s,
unsigned long ffio_get_checksum(AVIOContext *s);
unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf,
unsigned int len);
unsigned long ff_crcA001_update(unsigned long checksum, const uint8_t *buf,
unsigned int len);
/**
* Open a write only packetized memory stream with a maximum packet

6
libavformat/aviobuf.c
View File

@ -414,6 +414,12 @@ unsigned long ff_crc04C11DB7_update(unsigned long checksum, const uint8_t *buf,
return av_crc(av_crc_get_table(AV_CRC_32_IEEE), checksum, buf, len);
}
unsigned long ff_crcA001_update(unsigned long checksum, const uint8_t *buf,
unsigned int len)
{
return av_crc(av_crc_get_table(AV_CRC_16_ANSI_LE), checksum, buf, len);
}
unsigned long ffio_get_checksum(AVIOContext *s)
{
s->checksum = s->update_checksum(s->checksum, s->checksum_ptr,

103
libavformat/mp3dec.c
View File

@ -21,10 +21,12 @@
#include "libavutil/avstring.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/crc.h"
#include "libavutil/dict.h"
#include "libavutil/mathematics.h"
#include "avformat.h"
#include "internal.h"
#include "avio_internal.h"
#include "id3v2.h"
#include "id3v1.h"
#include "replaygain.h"
@ -128,11 +130,20 @@ static void read_xing_toc(AVFormatContext *s, int64_t filesize, int64_t duration
mp3->xing_toc = 1;
}
static void mp3_parse_info_tag(AVFormatContext *s, AVStream *st,
MPADecodeHeader *c, uint32_t spf)
{
#define LAST_BITS(k, n) ((k) & ((1 << (n)) - 1))
#define MIDDLE_BITS(k, m, n) LAST_BITS((k) >> (m), ((n) - (m)))
uint16_t crc;
uint32_t v;
char version[10];
uint32_t peak = 0;
int32_t r_gain = INT32_MIN, a_gain = INT32_MIN;
MP3DecContext *mp3 = s->priv_data;
const int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}};
@ -140,17 +151,87 @@ static void mp3_parse_info_tag(AVFormatContext *s, AVStream *st,
avio_skip(s->pb, xing_offtbl[c->lsf == 1][c->nb_channels == 1]);
v = avio_rb32(s->pb);
mp3->is_cbr = v == MKBETAG('I', 'n', 'f', 'o');
if (v == MKBETAG('X', 'i', 'n', 'g') || mp3->is_cbr) {
v = avio_rb32(s->pb);
if (v & XING_FLAG_FRAMES)
mp3->frames = avio_rb32(s->pb);
if (v & XING_FLAG_SIZE)
mp3->size = avio_rb32(s->pb);
if (v & XING_FLAG_TOC && mp3->frames)
read_xing_toc(s, mp3->size,
av_rescale_q(mp3->frames,
if (v != MKBETAG('X', 'i', 'n', 'g') && !mp3->is_cbr)
return;
v = avio_rb32(s->pb);
if (v & XING_FLAG_FRAMES)
mp3->frames = avio_rb32(s->pb);
if (v & XING_FLAG_SIZE)
mp3->size = avio_rb32(s->pb);
if (v & XING_FLAG_TOC && mp3->frames)
read_xing_toc(s, mp3->size, av_rescale_q(mp3->frames,
(AVRational){spf, c->sample_rate},
st->time_base));
/* VBR quality */
avio_rb32(s->pb);
/* Encoder short version string */
memset(version, 0, sizeof(version));
avio_read(s->pb, version, 9);
/* Info Tag revision + VBR method */
avio_r8(s->pb);
/* Lowpass filter value */
avio_r8(s->pb);
/* ReplayGain peak */
v = avio_rb32(s->pb);
peak = av_rescale(v, 100000, 1 << 23);
/* Radio ReplayGain */
v = avio_rb16(s->pb);
if (MIDDLE_BITS(v, 13, 15) == 1) {
r_gain = MIDDLE_BITS(v, 0, 8) * 10000;
if (v & (1 << 9))
r_gain *= -1;
}
/* Audiophile ReplayGain */
v = avio_rb16(s->pb);
if (MIDDLE_BITS(v, 13, 15) == 2) {
a_gain = MIDDLE_BITS(v, 0, 8) * 10000;
if (v & (1 << 9))
a_gain *= -1;
}
/* Encoding flags + ATH Type */
avio_r8(s->pb);
/* if ABR {specified bitrate} else {minimal bitrate} */
avio_r8(s->pb);
/* Encoder delays */
avio_rb24(s->pb);
/* Misc */
avio_r8(s->pb);
/* MP3 gain */
avio_r8(s->pb);
/* Preset and surround info */
avio_rb16(s->pb);
/* Music length */
avio_rb32(s->pb);
/* Music CRC */
avio_rb16(s->pb);
/* Info Tag CRC */
crc = ffio_get_checksum(s->pb);
v = avio_rb16(s->pb);
if (v == crc) {
ff_replaygain_export_raw(st, r_gain, peak, a_gain, 0);
av_dict_set(&st->metadata, "encoder", version, 0);
}
}
@ -183,6 +264,8 @@ static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base)
int vbrtag_size = 0;
MP3DecContext *mp3 = s->priv_data;
ffio_init_checksum(s->pb, ff_crcA001_update, 0);
v = avio_rb32(s->pb);
if(ff_mpa_check_header(v) < 0)
return -1;