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Code Issues Releases Activity

lavc/flac: Fix encoding and decoding with high lpc.

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Based on an analysis by trac user lvqcl.

Fixes ticket #4421, reported by Chase Walker.
This commit is contained in:
Carl Eugen Hoyos 2015-05-12 13:00:29 +02:00
parent 38f5a266ee
commit e609cfd697
8 changed files with 81 additions and 26 deletions
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17
doc/decoders.texi
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@ -83,6 +83,23 @@ Loud sounds are fully compressed. Soft sounds are enhanced.
@end table
@section flac
FLAC audio decoder.
This decoder aims to implement the complete FLAC specification from Xiph.
@subsection FLAC Decoder options
@table @option
@item -use_buggy_lpc
The lavc FLAC encoder used to produce buggy streams with high lpc values
(like the default value). This option allows to decode such streams
correctly by using lavc's old buggy lpc logic for decoding.
@end table
@section ffwavesynth
Internal wave synthetizer.

4
libavcodec/arm/flacdsp_init_arm.c
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@ -27,6 +27,6 @@ void ff_flac_lpc_16_arm(int32_t *samples, const int coeffs[32], int order,
av_cold void ff_flacdsp_init_arm(FLACDSPContext *c, enum AVSampleFormat fmt, int channels,
int bps)
{
if (CONFIG_FLAC_DECODER && bps <= 16)
c->lpc = ff_flac_lpc_16_arm;
if (CONFIG_FLAC_DECODER)
c->lpc16 = ff_flac_lpc_16_arm;
}

24
libavcodec/flacdec.c
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@ -35,6 +35,7 @@
#include "libavutil/avassert.h"
#include "libavutil/crc.h"
#include "libavutil/opt.h"
#include "avcodec.h"
#include "internal.h"
#include "get_bits.h"
@ -48,6 +49,7 @@
typedef struct FLACContext {
AVClass *class;
struct FLACStreaminfo flac_stream_info;
AVCodecContext *avctx; ///< parent AVCodecContext
@ -61,6 +63,7 @@ typedef struct FLACContext {
int32_t *decoded[FLAC_MAX_CHANNELS]; ///< decoded samples
uint8_t *decoded_buffer;
unsigned int decoded_buffer_size;
int buggy_lpc; ///< use workaround for old lavc encoded files
FLACDSPContext dsp;
} FLACContext;
@ -343,7 +346,13 @@ static int decode_subframe_lpc(FLACContext *s, int32_t *decoded, int pred_order,
if ((ret = decode_residuals(s, decoded, pred_order)) < 0)
return ret;
s->dsp.lpc(decoded, coeffs, pred_order, qlevel, s->blocksize);
if ( ( s->buggy_lpc && s->flac_stream_info.bps <= 16)
|| ( !s->buggy_lpc && bps <= 16
&& bps + coeff_prec + av_log2(pred_order) <= 32)) {
s->dsp.lpc16(decoded, coeffs, pred_order, qlevel, s->blocksize);
} else {
s->dsp.lpc32(decoded, coeffs, pred_order, qlevel, s->blocksize);
}
return 0;
}
@ -605,6 +614,18 @@ static av_cold int flac_decode_close(AVCodecContext *avctx)
return 0;
}
static const AVOption options[] = {
{ "use_buggy_lpc", "emulate old buggy lavc behavior", offsetof(FLACContext, buggy_lpc), AV_OPT_TYPE_INT, {.i64 = 0 }, 0, 1, AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_AUDIO_PARAM },
{ NULL },
};
static const AVClass flac_decoder_class = {
"FLAC decoder",
av_default_item_name,
options,
LIBAVUTIL_VERSION_INT,
};
AVCodec ff_flac_decoder = {
.name = "flac",
.long_name = NULL_IF_CONFIG_SMALL("FLAC (Free Lossless Audio Codec)"),
@ -621,4 +642,5 @@ AVCodec ff_flac_decoder = {
AV_SAMPLE_FMT_S32,
AV_SAMPLE_FMT_S32P,
AV_SAMPLE_FMT_NONE },
.priv_class = &flac_decoder_class,
};

11
libavcodec/flacdsp.c
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@ -88,13 +88,10 @@ static void flac_lpc_32_c(int32_t *decoded, const int coeffs[32],
av_cold void ff_flacdsp_init(FLACDSPContext *c, enum AVSampleFormat fmt, int channels,
int bps)
{
if (bps > 16) {
c->lpc = flac_lpc_32_c;
c->lpc_encode = flac_lpc_encode_c_32;
} else {
c->lpc = flac_lpc_16_c;
c->lpc_encode = flac_lpc_encode_c_16;
}
c->lpc16 = flac_lpc_16_c;
c->lpc32 = flac_lpc_32_c;
c->lpc16_encode = flac_lpc_encode_c_16;
c->lpc32_encode = flac_lpc_encode_c_32;
switch (fmt) {
case AV_SAMPLE_FMT_S32:

12
libavcodec/flacdsp.h
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@ -25,10 +25,14 @@
typedef struct FLACDSPContext {
void (*decorrelate[4])(uint8_t **out, int32_t **in, int channels,
int len, int shift);
void (*lpc)(int32_t *samples, const int coeffs[32], int order,
int qlevel, int len);
void (*lpc_encode)(int32_t *res, const int32_t *smp, int len, int order,
const int32_t coefs[32], int shift);
void (*lpc16)(int32_t *samples, const int coeffs[32], int order,
int qlevel, int len);
void (*lpc32)(int32_t *samples, const int coeffs[32], int order,
int qlevel, int len);
void (*lpc16_encode)(int32_t *res, const int32_t *smp, int len, int order,
const int32_t coefs[32], int shift);
void (*lpc32_encode)(int32_t *res, const int32_t *smp, int len, int order,
const int32_t coefs[32], int shift);
} FLACDSPContext;
void ff_flacdsp_init(FLACDSPContext *c, enum AVSampleFormat fmt, int channels, int bps);

27
libavcodec/flacenc.c
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@ -838,8 +838,13 @@ static int encode_residual_ch(FlacEncodeContext *s, int ch)
order = av_clip(order, min_order - 1, max_order - 1);
if (order == last_order)
continue;
s->flac_dsp.lpc_encode(res, smp, n, order+1, coefs[order],
shift[order]);
if (s->bps_code * 4 + s->options.lpc_coeff_precision + av_log2(order) <= 32) {
s->flac_dsp.lpc16_encode(res, smp, n, order+1, coefs[order],
shift[order]);
} else {
s->flac_dsp.lpc32_encode(res, smp, n, order+1, coefs[order],
shift[order]);
}
bits[i] = find_subframe_rice_params(s, sub, order+1);
if (bits[i] < bits[opt_index]) {
opt_index = i;
@ -853,7 +858,11 @@ static int encode_residual_ch(FlacEncodeContext *s, int ch)
opt_order = 0;
bits[0] = UINT32_MAX;
for (i = min_order-1; i < max_order; i++) {
s->flac_dsp.lpc_encode(res, smp, n, i+1, coefs[i], shift[i]);
if (s->bps_code * 4 + s->options.lpc_coeff_precision + av_log2(i) <= 32) {
s->flac_dsp.lpc16_encode(res, smp, n, i+1, coefs[i], shift[i]);
} else {
s->flac_dsp.lpc32_encode(res, smp, n, i+1, coefs[i], shift[i]);
}
bits[i] = find_subframe_rice_params(s, sub, i+1);
if (bits[i] < bits[opt_order])
opt_order = i;
@ -871,7 +880,11 @@ static int encode_residual_ch(FlacEncodeContext *s, int ch)
for (i = last-step; i <= last+step; i += step) {
if (i < min_order-1 || i >= max_order || bits[i] < UINT32_MAX)
continue;
s->flac_dsp.lpc_encode(res, smp, n, i+1, coefs[i], shift[i]);
if (s->bps_code * 4 + s->options.lpc_coeff_precision + av_log2(i) <= 32) {
s->flac_dsp.lpc32_encode(res, smp, n, i+1, coefs[i], shift[i]);
} else {
s->flac_dsp.lpc16_encode(res, smp, n, i+1, coefs[i], shift[i]);
}
bits[i] = find_subframe_rice_params(s, sub, i+1);
if (bits[i] < bits[opt_order])
opt_order = i;
@ -886,7 +899,11 @@ static int encode_residual_ch(FlacEncodeContext *s, int ch)
for (i = 0; i < sub->order; i++)
sub->coefs[i] = coefs[sub->order-1][i];
s->flac_dsp.lpc_encode(res, smp, n, sub->order, sub->coefs, sub->shift);
if (s->bps_code * 4 + s->options.lpc_coeff_precision + av_log2(opt_order) <= 32) {
s->flac_dsp.lpc16_encode(res, smp, n, sub->order, sub->coefs, sub->shift);
} else {
s->flac_dsp.lpc32_encode(res, smp, n, sub->order, sub->coefs, sub->shift);
}
find_subframe_rice_params(s, sub, sub->order);

2
libavcodec/version.h
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@ -30,7 +30,7 @@
#define LIBAVCODEC_VERSION_MAJOR 56
#define LIBAVCODEC_VERSION_MINOR 39
#define LIBAVCODEC_VERSION_MICRO 100
#define LIBAVCODEC_VERSION_MICRO 101
#define LIBAVCODEC_VERSION_INT AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
LIBAVCODEC_VERSION_MINOR, \

10
libavcodec/x86/flacdsp_init.c
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@ -85,8 +85,7 @@ av_cold void ff_flacdsp_init_x86(FLACDSPContext *c, enum AVSampleFormat fmt, int
}
}
if (EXTERNAL_SSE4(cpu_flags)) {
if (bps > 16)
c->lpc = ff_flac_lpc_32_sse4;
c->lpc32 = ff_flac_lpc_32_sse4;
}
if (EXTERNAL_AVX(cpu_flags)) {
if (fmt == AV_SAMPLE_FMT_S16) {
@ -102,15 +101,14 @@ av_cold void ff_flacdsp_init_x86(FLACDSPContext *c, enum AVSampleFormat fmt, int
}
}
if (EXTERNAL_XOP(cpu_flags)) {
if (bps > 16)
c->lpc = ff_flac_lpc_32_xop;
c->lpc32 = ff_flac_lpc_32_xop;
}
#endif
#if CONFIG_FLAC_ENCODER
if (EXTERNAL_SSE4(cpu_flags)) {
if (CONFIG_GPL && bps == 16)
c->lpc_encode = ff_flac_enc_lpc_16_sse4;
if (CONFIG_GPL)
c->lpc16_encode = ff_flac_enc_lpc_16_sse4;
}
#endif
#endif /* HAVE_YASM */