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avcodec/siren: MSN Siren decoder

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Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Peter Ross <pross@xvid.org>
This commit is contained in:
Peter Ross 2021-09-04 17:22:19 +10:00
parent b9426f371a
commit c655a734b1
8 changed files with 70 additions and 3 deletions
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59
libavcodec/siren.c
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@ -359,11 +359,13 @@ static const float noise_category6[21] = {
typedef struct SirenContext {
GetBitContext gb;
int microsoft;
int rate_control_possibilities;
int esf_adjustment;
int number_of_regions;
int scale_factor;
int sample_rate_bits;
int checksum_bits;
unsigned dw1, dw2, dw3, dw4;
@ -421,6 +423,15 @@ static av_cold int siren_init(AVCodecContext *avctx)
if (!s->fdsp)
return AVERROR(ENOMEM);
s->microsoft = avctx->codec->id == AV_CODEC_ID_MSNSIREN;
if (s->microsoft) {
s->esf_adjustment = -2;
s->number_of_regions = 14;
s->scale_factor = 1;
s->sample_rate_bits = 2;
s->checksum_bits = 4;
}
return av_tx_init(&s->tx_ctx, &s->tx_fn, AV_TX_FLOAT_MDCT, 1, FRAME_SIZE, &scale, 0);
}
@ -626,6 +637,20 @@ static int decode_vector(SirenContext *s, int number_of_regions,
coefs_ptr = coefs + (region * REGION_SIZE);
if (category == 5 && s->microsoft) {
i = 0;
for (j = 0; j < REGION_SIZE; j++) {
if (*coefs_ptr != 0) {
i++;
if (fabs(*coefs_ptr) > 2.0 * decoder_standard_deviation[region]) {
i += 3;
}
}
coefs_ptr++;
}
noise = decoder_standard_deviation[region] * noise_category5[i];
} else
if (category == 5 || category == 6) {
i = 0;
for (j = 0; j < REGION_SIZE; j++) {
@ -675,10 +700,22 @@ static int siren_decode(AVCodecContext *avctx, void *data,
AVFrame *frame = data;
int ret, number_of_valid_coefs = 20 * s->number_of_regions;
int frame_error = 0, rate_control = 0;
int bits_per_frame;
if (s->microsoft) {
bits_per_frame = avctx->sample_rate / 50;
if (avpkt->size < bits_per_frame / 8)
return AVERROR_INVALIDDATA;
if ((ret = init_get_bits(gb, avpkt->data, bits_per_frame - s->checksum_bits)) < 0)
return ret;
} else
if ((ret = init_get_bits8(gb, avpkt->data, avpkt->size)) < 0)
return ret;
skip_bits(gb, s->sample_rate_bits);
decode_envelope(s, gb, s->number_of_regions,
s->decoder_standard_deviation,
s->absolute_region_power_index, s->esf_adjustment);
@ -697,7 +734,7 @@ static int siren_decode(AVCodecContext *avctx, void *data,
ret = decode_vector(s, s->number_of_regions, get_bits_left(gb),
s->decoder_standard_deviation, s->power_categories,
s->imdct_in, s->scale_factor);
if (ret < 0)
if (ret < 0 && !s->microsoft)
return ret;
if (get_bits_left(gb) > 0) {
@ -715,6 +752,8 @@ static int siren_decode(AVCodecContext *avctx, void *data,
frame_error = 1;
}
skip_bits(gb, s->checksum_bits);
if (frame_error) {
memcpy(s->imdct_in, s->backup_frame, number_of_valid_coefs * sizeof(float));
memset(s->backup_frame, 0, number_of_valid_coefs * sizeof(float));
@ -738,7 +777,7 @@ static int siren_decode(AVCodecContext *avctx, void *data,
*got_frame = 1;
return avpkt->size;
return s->microsoft ? bits_per_frame / 8 : avpkt->size;
}
static av_cold void siren_flush(AVCodecContext *avctx)
@ -775,3 +814,19 @@ const AVCodec ff_siren_decoder = {
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE |
FF_CODEC_CAP_INIT_CLEANUP,
};
const AVCodec ff_msnsiren_decoder = {
.name = "msnsiren",
.long_name = NULL_IF_CONFIG_SMALL("MSN Siren"),
.priv_data_size = sizeof(SirenContext),
.type = AVMEDIA_TYPE_AUDIO,
.id = AV_CODEC_ID_MSNSIREN,
.init = siren_init,
.close = siren_close,
.decode = siren_decode,
.flush = siren_flush,
.capabilities = AV_CODEC_CAP_CHANNEL_CONF |
AV_CODEC_CAP_DR1,
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE |
FF_CODEC_CAP_INIT_CLEANUP,
};