39 int sample_rate_index, bitrate_index;
47 s->lsf = (
header & (1<<19)) ? 0 : 1;
54 s->layer = 4 - ((
header >> 17) & 3);
56 sample_rate_index = (
header >> 10) & 3;
58 sample_rate_index = 0;
60 sample_rate_index += 3 * (
s->lsf + mpeg25);
61 s->sample_rate_index = sample_rate_index;
62 s->error_protection = ((
header >> 16) & 1) ^ 1;
65 bitrate_index = (
header >> 12) & 0xf;
66 padding = (
header >> 9) & 1;
69 s->mode_ext = (
header >> 4) & 3;
79 if (bitrate_index != 0) {
105 s->layer,
s->sample_rate,
s->bit_rate);
106 if (
s->nb_channels == 2) {
152 *bit_rate =
s->bit_rate;
153 return s->frame_size;
Libavcodec external API header.
common internal and external API header
AVCodecID
Identify the syntax and semantics of the bitstream.
@ AV_CODEC_ID_MP3
preferred ID for decoding MPEG audio layer 1, 2 or 3
common internal API header
mpeg audio declarations for both encoder and decoder.
const uint16_t avpriv_mpa_freq_tab[3]
const uint16_t avpriv_mpa_bitrate_tab[2][3][15]
mpeg audio layer common tables.
#define MODE_EXT_MS_STEREO
#define MODE_EXT_I_STEREO
static const uint8_t header[24]
#define FF_ARRAY_ELEMS(a)