@ -75,20 +75,22 @@ typedef struct AlacEncodeContext {
} AlacEncodeContext ; } AlacEncodeContext ;
static void init_sample_buffers ( AlacEncodeContext * s , const int16_t * input_samples ) static void init_sample_buffers ( AlacEncodeContext * s ,
const int16_t * input_samples )
{ {
int ch , i ; int ch , i ;
for ( ch = 0 ; ch < s - > avctx - > channels ; ch + + ) { for ( ch = 0 ; ch < s - > avctx - > channels ; ch + + ) {
const int16_t * sptr = input_samples + ch ; const int16_t * sptr = input_samples + ch ;
for ( i = 0 ; i < s - > avctx - > frame_size ; i + + ) { for ( i = 0 ; i < s - > avctx - > frame_size ; i + + ) {
s - > sample_buf [ ch ] [ i ] = * sptr ; s - > sample_buf [ ch ] [ i ] = * sptr ;
sptr + = s - > avctx - > channels ; sptr + = s - > avctx - > channels ;
} }
} }
} }
static void encode_scalar ( AlacEncodeContext * s , int x , int k , int write_sample_size ) static void encode_scalar ( AlacEncodeContext * s , int x ,
int k , int write_sample_size )
{ {
int divisor , q , r ; int divisor , q , r ;
@ -97,17 +99,17 @@ static void encode_scalar(AlacEncodeContext *s, int x, int k, int write_sample_s
q = x / divisor ; q = x / divisor ;
r = x % divisor ; r = x % divisor ;
if ( q > 8 ) { if ( q > 8 ) {
// write escape code and sample value directly
// write escape code and sample value directly
put_bits ( & s - > pbctx , 9 , ALAC_ESCAPE_CODE ) ; put_bits ( & s - > pbctx , 9 , ALAC_ESCAPE_CODE ) ;
put_bits ( & s - > pbctx , write_sample_size , x ) ; put_bits ( & s - > pbctx , write_sample_size , x ) ;
} else { } else {
if ( q ) if ( q )
put_bits ( & s - > pbctx , q , ( 1 < < q ) - 1 ) ; put_bits ( & s - > pbctx , q , ( 1 < < q ) - 1 ) ;
put_bits ( & s - > pbctx , 1 , 0 ) ; put_bits ( & s - > pbctx , 1 , 0 ) ;
if ( k ! = 1 ) { if ( k ! = 1 ) {
if ( r > 0 ) if ( r > 0 )
put_bits ( & s - > pbctx , k , r + 1 ) ; put_bits ( & s - > pbctx , k , r + 1 ) ;
else else
put_bits ( & s - > pbctx , k - 1 , 0 ) ; put_bits ( & s - > pbctx , k - 1 , 0 ) ;
@ -164,7 +166,7 @@ static int estimate_stereo_mode(int32_t *left_ch, int32_t *right_ch, int n)
/* calculate sum of 2nd order residual for each channel */ /* calculate sum of 2nd order residual for each channel */
sum [ 0 ] = sum [ 1 ] = sum [ 2 ] = sum [ 3 ] = 0 ; sum [ 0 ] = sum [ 1 ] = sum [ 2 ] = sum [ 3 ] = 0 ;
for ( i = 2 ; i < n ; i + + ) { for ( i = 2 ; i < n ; i + + ) {
lt = left_ch [ i ] - 2 * left_ch [ i - 1 ] + left_ch [ i - 2 ] ; lt = left_ch [ i ] - 2 * left_ch [ i - 1 ] + left_ch [ i - 2 ] ;
rt = right_ch [ i ] - 2 * right_ch [ i - 1 ] + right_ch [ i - 2 ] ; rt = right_ch [ i ] - 2 * right_ch [ i - 1 ] + right_ch [ i - 2 ] ;
sum [ 2 ] + = FFABS ( ( lt + rt ) > > 1 ) ; sum [ 2 ] + = FFABS ( ( lt + rt ) > > 1 ) ;
@ -181,8 +183,8 @@ static int estimate_stereo_mode(int32_t *left_ch, int32_t *right_ch, int n)
/* return mode with lowest score */ /* return mode with lowest score */
best = 0 ; best = 0 ;
for ( i = 1 ; i < 4 ; i + + ) { for ( i = 1 ; i < 4 ; i + + ) {
if ( score [ i ] < score [ best ] ) { if ( score [ i ] < score [ best ] ) {
best = i ; best = i ;
} }
} }
@ -205,7 +207,7 @@ static void alac_stereo_decorrelation(AlacEncodeContext *s)
break ; break ;
case ALAC_CHMODE_LEFT_SIDE : case ALAC_CHMODE_LEFT_SIDE :
for ( i = 0 ; i < n ; i + + ) { for ( i = 0 ; i < n ; i + + ) {
right [ i ] = left [ i ] - right [ i ] ; right [ i ] = left [ i ] - right [ i ] ;
} }
s - > interlacing_leftweight = 1 ; s - > interlacing_leftweight = 1 ;
@ -213,7 +215,7 @@ static void alac_stereo_decorrelation(AlacEncodeContext *s)
break ; break ;
case ALAC_CHMODE_RIGHT_SIDE : case ALAC_CHMODE_RIGHT_SIDE :
for ( i = 0 ; i < n ; i + + ) { for ( i = 0 ; i < n ; i + + ) {
tmp = right [ i ] ; tmp = right [ i ] ;
right [ i ] = left [ i ] - right [ i ] ; right [ i ] = left [ i ] - right [ i ] ;
left [ i ] = tmp + ( right [ i ] > > 31 ) ; left [ i ] = tmp + ( right [ i ] > > 31 ) ;
@ -223,7 +225,7 @@ static void alac_stereo_decorrelation(AlacEncodeContext *s)
break ; break ;
default : default :
for ( i = 0 ; i < n ; i + + ) { for ( i = 0 ; i < n ; i + + ) {
tmp = left [ i ] ; tmp = left [ i ] ;
left [ i ] = ( tmp + right [ i ] ) > > 1 ; left [ i ] = ( tmp + right [ i ] ) > > 1 ;
right [ i ] = tmp - right [ i ] ; right [ i ] = tmp - right [ i ] ;
@ -239,10 +241,10 @@ static void alac_linear_predictor(AlacEncodeContext *s, int ch)
int i ; int i ;
AlacLPCContext lpc = s - > lpc [ ch ] ; AlacLPCContext lpc = s - > lpc [ ch ] ;
if ( lpc . lpc_order = = 31 ) { if ( lpc . lpc_order = = 31 ) {
s - > predictor_buf [ 0 ] = s - > sample_buf [ ch ] [ 0 ] ; s - > predictor_buf [ 0 ] = s - > sample_buf [ ch ] [ 0 ] ;
for ( i = 1 ; i < s - > avctx - > frame_size ; i + + ) for ( i = 1 ; i < s - > avctx - > frame_size ; i + + )
s - > predictor_buf [ i ] = s - > sample_buf [ ch ] [ i ] - s - > sample_buf [ ch ] [ i - 1 ] ; s - > predictor_buf [ i ] = s - > sample_buf [ ch ] [ i ] - s - > sample_buf [ ch ] [ i - 1 ] ;
return ; return ;
@ -250,17 +252,17 @@ static void alac_linear_predictor(AlacEncodeContext *s, int ch)
// generalised linear predictor
// generalised linear predictor
if ( lpc . lpc_order > 0 ) { if ( lpc . lpc_order > 0 ) {
int32_t * samples = s - > sample_buf [ ch ] ; int32_t * samples = s - > sample_buf [ ch ] ;
int32_t * residual = s - > predictor_buf ; int32_t * residual = s - > predictor_buf ;
// generate warm-up samples
// generate warm-up samples
residual [ 0 ] = samples [ 0 ] ; residual [ 0 ] = samples [ 0 ] ;
for ( i = 1 ; i < = lpc . lpc_order ; i + + ) for ( i = 1 ; i < = lpc . lpc_order ; i + + )
residual [ i ] = samples [ i ] - samples [ i - 1 ] ; residual [ i ] = samples [ i ] - samples [ i - 1 ] ;
// perform lpc on remaining samples
// perform lpc on remaining samples
for ( i = lpc . lpc_order + 1 ; i < s - > avctx - > frame_size ; i + + ) { for ( i = lpc . lpc_order + 1 ; i < s - > avctx - > frame_size ; i + + ) {
int sum = 1 < < ( lpc . lpc_quant - 1 ) , res_val , j ; int sum = 1 < < ( lpc . lpc_quant - 1 ) , res_val , j ;
for ( j = 0 ; j < lpc . lpc_order ; j + + ) { for ( j = 0 ; j < lpc . lpc_order ; j + + ) {
@ -303,7 +305,7 @@ static void alac_entropy_coder(AlacEncodeContext *s)
int sign_modifier = 0 , i , k ; int sign_modifier = 0 , i , k ;
int32_t * samples = s - > predictor_buf ; int32_t * samples = s - > predictor_buf ;
for ( i = 0 ; i < s - > avctx - > frame_size ; ) { for ( i = 0 ; i < s - > avctx - > frame_size ; ) {
int x ; int x ;
k = av_log2 ( ( history > > 9 ) + 3 ) ; k = av_log2 ( ( history > > 9 ) + 3 ) ;
@ -320,15 +322,15 @@ static void alac_entropy_coder(AlacEncodeContext *s)
- ( ( history * s - > rc . history_mult ) > > 9 ) ; - ( ( history * s - > rc . history_mult ) > > 9 ) ;
sign_modifier = 0 ; sign_modifier = 0 ;
if ( x > 0xFFFF ) if ( x > 0xFFFF )
history = 0xFFFF ; history = 0xFFFF ;
if ( ( history < 128 ) & & ( i < s - > avctx - > frame_size ) ) { if ( history < 128 & & i < s - > avctx - > frame_size ) {
unsigned int block_size = 0 ; unsigned int block_size = 0 ;
k = 7 - av_log2 ( history ) + ( ( history + 16 ) > > 6 ) ; k = 7 - av_log2 ( history ) + ( ( history + 16 ) > > 6 ) ;
while ( ( * samples = = 0 ) & & ( i < s - > avctx - > frame_size ) ) { while ( * samples = = 0 & & i < s - > avctx - > frame_size ) {
samples + + ; samples + + ;
i + + ; i + + ;
block_size + + ; block_size + + ;
@ -347,12 +349,12 @@ static void write_compressed_frame(AlacEncodeContext *s)
{ {
int i , j ; int i , j ;
if ( s - > avctx - > channels = = 2 ) if ( s - > avctx - > channels = = 2 )
alac_stereo_decorrelation ( s ) ; alac_stereo_decorrelation ( s ) ;
put_bits ( & s - > pbctx , 8 , s - > interlacing_shift ) ; put_bits ( & s - > pbctx , 8 , s - > interlacing_shift ) ;
put_bits ( & s - > pbctx , 8 , s - > interlacing_leftweight ) ; put_bits ( & s - > pbctx , 8 , s - > interlacing_leftweight ) ;
for ( i = 0 ; i < s - > avctx - > channels ; i + + ) { for ( i = 0 ; i < s - > avctx - > channels ; i + + ) {
calc_predictor_params ( s , i ) ; calc_predictor_params ( s , i ) ;
@ -362,14 +364,14 @@ static void write_compressed_frame(AlacEncodeContext *s)
put_bits ( & s - > pbctx , 3 , s - > rc . rice_modifier ) ; put_bits ( & s - > pbctx , 3 , s - > rc . rice_modifier ) ;
put_bits ( & s - > pbctx , 5 , s - > lpc [ i ] . lpc_order ) ; put_bits ( & s - > pbctx , 5 , s - > lpc [ i ] . lpc_order ) ;
// predictor coeff. table
// predictor coeff. table
for ( j = 0 ; j < s - > lpc [ i ] . lpc_order ; j + + ) { for ( j = 0 ; j < s - > lpc [ i ] . lpc_order ; j + + ) {
put_sbits ( & s - > pbctx , 16 , s - > lpc [ i ] . lpc_coeff [ j ] ) ; put_sbits ( & s - > pbctx , 16 , s - > lpc [ i ] . lpc_coeff [ j ] ) ;
} }
} }
// apply lpc and entropy coding to audio samples
// apply lpc and entropy coding to audio samples
for ( i = 0 ; i < s - > avctx - > channels ; i + + ) { for ( i = 0 ; i < s - > avctx - > channels ; i + + ) {
alac_linear_predictor ( s , i ) ; alac_linear_predictor ( s , i ) ;
alac_entropy_coder ( s ) ; alac_entropy_coder ( s ) ;
} }
@ -384,7 +386,7 @@ static av_cold int alac_encode_init(AVCodecContext *avctx)
avctx - > frame_size = DEFAULT_FRAME_SIZE ; avctx - > frame_size = DEFAULT_FRAME_SIZE ;
avctx - > bits_per_coded_sample = DEFAULT_SAMPLE_SIZE ; avctx - > bits_per_coded_sample = DEFAULT_SAMPLE_SIZE ;
if ( avctx - > sample_fmt ! = AV_SAMPLE_FMT_S16 ) { if ( avctx - > sample_fmt ! = AV_SAMPLE_FMT_S16 ) {
av_log ( avctx , AV_LOG_ERROR , " only pcm_s16 input samples are supported \n " ) ; av_log ( avctx , AV_LOG_ERROR , " only pcm_s16 input samples are supported \n " ) ;
return - 1 ; return - 1 ;
} }
@ -395,7 +397,7 @@ static av_cold int alac_encode_init(AVCodecContext *avctx)
} }
// Set default compression level
// Set default compression level
if ( avctx - > compression_level = = FF_COMPRESSION_DEFAULT ) if ( avctx - > compression_level = = FF_COMPRESSION_DEFAULT )
s - > compression_level = 2 ; s - > compression_level = 2 ;
else else
s - > compression_level = av_clip ( avctx - > compression_level , 0 , 2 ) ; s - > compression_level = av_clip ( avctx - > compression_level , 0 , 2 ) ;
@ -416,21 +418,23 @@ static av_cold int alac_encode_init(AVCodecContext *avctx)
AV_WB8 ( alac_extradata + 17 , avctx - > bits_per_coded_sample ) ; AV_WB8 ( alac_extradata + 17 , avctx - > bits_per_coded_sample ) ;
AV_WB8 ( alac_extradata + 21 , avctx - > channels ) ; AV_WB8 ( alac_extradata + 21 , avctx - > channels ) ;
AV_WB32 ( alac_extradata + 24 , s - > max_coded_frame_size ) ; AV_WB32 ( alac_extradata + 24 , s - > max_coded_frame_size ) ;
AV_WB32 ( alac_extradata + 28 , avctx - > sample_rate * avctx - > channels * avctx - > bits_per_coded_sample ) ; // average bitrate
AV_WB32 ( alac_extradata + 28 ,
avctx - > sample_rate * avctx - > channels * avctx - > bits_per_coded_sample ) ; // average bitrate
AV_WB32 ( alac_extradata + 32 , avctx - > sample_rate ) ; AV_WB32 ( alac_extradata + 32 , avctx - > sample_rate ) ;
// Set relevant extradata fields
// Set relevant extradata fields
if ( s - > compression_level > 0 ) { if ( s - > compression_level > 0 ) {
AV_WB8 ( alac_extradata + 18 , s - > rc . history_mult ) ; AV_WB8 ( alac_extradata + 18 , s - > rc . history_mult ) ;
AV_WB8 ( alac_extradata + 19 , s - > rc . initial_history ) ; AV_WB8 ( alac_extradata + 19 , s - > rc . initial_history ) ;
AV_WB8 ( alac_extradata + 20 , s - > rc . k_modifier ) ; AV_WB8 ( alac_extradata + 20 , s - > rc . k_modifier ) ;
} }
s - > min_prediction_order = DEFAULT_MIN_PRED_ORDER ; s - > min_prediction_order = DEFAULT_MIN_PRED_ORDER ;
if ( avctx - > min_prediction_order > = 0 ) { if ( avctx - > min_prediction_order > = 0 ) {
if ( avctx - > min_prediction_order < MIN_LPC_ORDER | | if ( avctx - > min_prediction_order < MIN_LPC_ORDER | |
avctx - > min_prediction_order > ALAC_MAX_LPC_ORDER ) { avctx - > min_prediction_order > ALAC_MAX_LPC_ORDER ) {
av_log ( avctx , AV_LOG_ERROR , " invalid min prediction order: %d \n " , avctx - > min_prediction_order ) ; av_log ( avctx , AV_LOG_ERROR , " invalid min prediction order: %d \n " ,
avctx - > min_prediction_order ) ;
return - 1 ; return - 1 ;
} }
@ -438,18 +442,20 @@ static av_cold int alac_encode_init(AVCodecContext *avctx)
} }
s - > max_prediction_order = DEFAULT_MAX_PRED_ORDER ; s - > max_prediction_order = DEFAULT_MAX_PRED_ORDER ;
if ( avctx - > max_prediction_order > = 0 ) { if ( avctx - > max_prediction_order > = 0 ) {
if ( avctx - > max_prediction_order < MIN_LPC_ORDER | | if ( avctx - > max_prediction_order < MIN_LPC_ORDER | |
avctx - > max_prediction_order > ALAC_MAX_LPC_ORDER ) { avctx - > max_prediction_order > ALAC_MAX_LPC_ORDER ) {
av_log ( avctx , AV_LOG_ERROR , " invalid max prediction order: %d \n " , avctx - > max_prediction_order ) ; av_log ( avctx , AV_LOG_ERROR , " invalid max prediction order: %d \n " ,
avctx - > max_prediction_order ) ;
return - 1 ; return - 1 ;
} }
s - > max_prediction_order = avctx - > max_prediction_order ; s - > max_prediction_order = avctx - > max_prediction_order ;
} }
if ( s - > max_prediction_order < s - > min_prediction_order ) { if ( s - > max_prediction_order < s - > min_prediction_order ) {
av_log ( avctx , AV_LOG_ERROR , " invalid prediction orders: min=%d max=%d \n " , av_log ( avctx , AV_LOG_ERROR ,
" invalid prediction orders: min=%d max=%d \n " ,
s - > min_prediction_order , s - > max_prediction_order ) ; s - > min_prediction_order , s - > max_prediction_order ) ;
return - 1 ; return - 1 ;
} }
@ -474,12 +480,12 @@ static int alac_encode_frame(AVCodecContext *avctx, uint8_t *frame,
PutBitContext * pb = & s - > pbctx ; PutBitContext * pb = & s - > pbctx ;
int i , out_bytes , verbatim_flag = 0 ; int i , out_bytes , verbatim_flag = 0 ;
if ( avctx - > frame_size > DEFAULT_FRAME_SIZE ) { if ( avctx - > frame_size > DEFAULT_FRAME_SIZE ) {
av_log ( avctx , AV_LOG_ERROR , " input frame size exceeded \n " ) ; av_log ( avctx , AV_LOG_ERROR , " input frame size exceeded \n " ) ;
return - 1 ; return - 1 ;
} }
if ( buf_size < 2 * s - > max_coded_frame_size ) { if ( buf_size < 2 * s - > max_coded_frame_size ) {
av_log ( avctx , AV_LOG_ERROR , " buffer size is too small \n " ) ; av_log ( avctx , AV_LOG_ERROR , " buffer size is too small \n " ) ;
return - 1 ; return - 1 ;
} }
@ -487,11 +493,11 @@ static int alac_encode_frame(AVCodecContext *avctx, uint8_t *frame,
verbatim : verbatim :
init_put_bits ( pb , frame , buf_size ) ; init_put_bits ( pb , frame , buf_size ) ;
if ( ( s - > compression_level = = 0 ) | | verbatim_flag ) { if ( s - > compression_level = = 0 | | verbatim_flag ) {
// Verbatim mode
// Verbatim mode
const int16_t * samples = data ; const int16_t * samples = data ;
write_frame_header ( s , 1 ) ; write_frame_header ( s , 1 ) ;
for ( i = 0 ; i < avctx - > frame_size * avctx - > channels ; i + + ) { for ( i = 0 ; i < avctx - > frame_size * avctx - > channels ; i + + ) {
put_sbits ( pb , 16 , * samples + + ) ; put_sbits ( pb , 16 , * samples + + ) ;
} }
} else { } else {
@ -504,9 +510,9 @@ verbatim:
flush_put_bits ( pb ) ; flush_put_bits ( pb ) ;
out_bytes = put_bits_count ( pb ) > > 3 ; out_bytes = put_bits_count ( pb ) > > 3 ;
if ( out_bytes > s - > max_coded_frame_size ) { if ( out_bytes > s - > max_coded_frame_size ) {
/* frame too large. use verbatim mode */ /* frame too large. use verbatim mode */
if ( verbatim_flag | | ( s - > compression_level = = 0 ) ) { if ( verbatim_flag | | s - > compression_level = = 0 ) {
/* still too large. must be an error. */ /* still too large. must be an error. */
av_log ( avctx , AV_LOG_ERROR , " error encoding frame \n " ) ; av_log ( avctx , AV_LOG_ERROR , " error encoding frame \n " ) ;
return - 1 ; return - 1 ;
@ -537,6 +543,7 @@ AVCodec ff_alac_encoder = {
. encode = alac_encode_frame , . encode = alac_encode_frame ,
. close = alac_encode_close , . close = alac_encode_close ,
. capabilities = CODEC_CAP_SMALL_LAST_FRAME , . capabilities = CODEC_CAP_SMALL_LAST_FRAME ,
. sample_fmts = ( const enum AVSampleFormat [ ] ) { AV_SAMPLE_FMT_S16 , AV_SAMPLE_FMT_NONE } , . sample_fmts = ( const enum AVSampleFormat [ ] ) { AV_SAMPLE_FMT_S16 ,
AV_SAMPLE_FMT_NONE } ,
. long_name = NULL_IF_CONFIG_SMALL ( " ALAC (Apple Lossless Audio Codec) " ) , . long_name = NULL_IF_CONFIG_SMALL ( " ALAC (Apple Lossless Audio Codec) " ) ,
} ; } ;
Michael Niedermayer
13 years ago