[FFmpeg-devel] Nellymoser encoder
Michael Niedermayer
michaelni
Fri Aug 29 15:54:32 CEST 2008
On Fri, Aug 29, 2008 at 03:11:59PM +0200, Bartlomiej Wolowiec wrote:
> Friday 29 August 2008 00:02:36 Michael Niedermayer napisa?(a):
> > > +#define LUT_init_add -3134
> > > +#define LUT_init_size 31355 + LUT_init_add
> > > +static int LUT_init_table[LUT_init_size];
> >
> > i do not belive that the table needs to be that large
> >
> > > +
> > > +#define LUT_delta_add 11725
> > > +#define LUT_delta_size 12975 + LUT_delta_add
> > > +static int LUT_delta_table[LUT_delta_size];
> > > +
> > > +#define LUT_dequantization_mul 128.0
> > > +#define LUT_dequantization_add LUT_dequantization_mul * 2.7
> > > +#define LUT_dequantization_size (int)(LUT_dequantization_mul * 2.5 +
> > > LUT_dequantization_add) +#define LUT_dequantization_maxbits 6
> > > +static int
> > > LUT_dequantization_table[LUT_dequantization_maxbits][LUT_dequantization_s
> > >ize];
> >
> > neither do i belive that this one needs to be that large
> > besides they both can be uint8_t instead of int
> >
> > and the tables for fewer bits dont need to be as large as the largest
>
> Ok, I've tried to change sizes of these arrays. Unfortunately, now I have a
> problem, because I don't know how I can simply allocate memory for
> LUT_dequantization_table so that the whole is thread-safety.
drop all the messy stuff and the problems will disapear
>
> > > +
> > > +void apply_mdct(NellyMoserEncodeContext *s, float *in, float *coefs)
> > > +{
> > > + DECLARE_ALIGNED_16(float, in_buff[NELLY_SAMPLES]);
> > > +
> > > + memcpy(&in_buff[0], &in[0], NELLY_SAMPLES * sizeof(float));
> > > + s->dsp.vector_fmul(in_buff, ff_sine_128, NELLY_BUF_LEN);
> > > + s->dsp.vector_fmul_reverse(in_buff + NELLY_BUF_LEN, in_buff +
> > > NELLY_BUF_LEN, ff_sine_128, NELLY_BUF_LEN); +
> > > ff_mdct_calc(&s->mdct_ctx, coefs, in_buff);
> > > +}
> >
> > The data is copied once in encode_frame and twice here
> > There is no need to copy the data 3 times.
> > vector_fmul can be used with a singl memcpy to get the data into any
> > destination, and vector_fmul_reverse doesnt even need 1 memcpy, so
> > overall a single memcpy is enough
> >
> >
>
> Hope that you meant something similar to my solution.
no, you still do 2 memcpy() but now the code is really messy as well.
what you should do is, for each block of samples you get from the user
1. apply one half of the window onto it with vector_fmul_reverse and
destination of some internal buffer
2. memcpy into the 2nd destination and apply the other half of the
window onto it with vector_fmul
3. run the mdct as appropriate on the internal buffers.
>
> > [...]
> >
> > > +#define find_best(val, table, LUT, LUT_add, LUT_mul, LUT_size) \
> > > + best_idx = \
> > > + LUT[av_clip (lrintf(val * LUT_mul + LUT_add), 0, LUT_size - 1)];
> > > \ + if (fabs(val - table[best_idx]) > fabs(val - table[best_idx + 1]))
> > > \ + best_idx++;
> >
> > this can be an inline function which would be cleaner
> >
> >
> > [...]
>
> it's possible, but I don't know how to do it, because table may have float
> type, uint16_t or int16_t
ok, ive indeed missed that, but if the type can be int and float then this
is not acceptable as such because fabs() would convert to float and back when
the input is int.
which brings us back to the begin of that this macro isnt a good idea, and
that the single use of the float one can be just written where its used and
the other coukd either as well or be an inline function.
[...]
> +/**
> + * @file nellymoserenc.c
> + * Nellymoser encoder
> + * by Bartlomiej Wolowiec
> + *
> + * Generic codec information: libavcodec/nellymoserdec.c
> + * Log search algorithm idea: http://www1.mplayerhq.hu/ASAO/ASAO.zip
> + * (Copyright Joseph Artsimovich and UAB "DKD")
is this still in the code?
> + *
> + * for more information about nellymoser format, visit:
> + * http://wiki.multimedia.cx/index.php?title=Nellymoser
> + */
> +
> +#include "nellymoser.h"
> +#include "avcodec.h"
> +#include "dsputil.h"
> +
> +#define BITSTREAM_WRITER_LE
> +#include "bitstream.h"
> +
> +#define POW_TABLE_SIZE (1<<11)
> +#define POW_TABLE_OFFSET 3
> +
> +typedef struct NellyMoserEncodeContext {
> + AVCodecContext *avctx;
> + int last_frame;
> + int bufsel;
> + int have_saved;
> + DSPContext dsp;
> + MDCTContext mdct_ctx;
> + DECLARE_ALIGNED_16(float, mdct_out[NELLY_SAMPLES]);
> + DECLARE_ALIGNED_16(float, buf[2][3 * NELLY_BUF_LEN]); ///< sample buffer
> +} NellyMoserEncodeContext;
> +
> +static float pow_table[POW_TABLE_SIZE]; ///< -pow(2, -i / 2048.0 - 3.0);
> +
> +#define LUT_init_mul (1.0/256.0)
please do not use floats to >> of integers
> +#define LUT_init_add (-3134 * LUT_init_mul)
> +#define LUT_init_size (int)(LUT_init_mul * 31355 + LUT_init_add)
> +static uint8_t LUT_init_table[LUT_init_size];
static const uint8_t sf_lut[123]={
...
}
> +
> +#define LUT_delta_mul (1.0/256.0)
> +#define LUT_delta_add (LUT_delta_mul * 11725)
> +#define LUT_delta_size (int)(LUT_delta_mul * 12975 + LUT_delta_add)
> +static uint8_t LUT_delta_table[LUT_delta_size];
static const uint8_t sf_delta_lut[123]={
...
}
> +
> +#define LUT_dequantization_maxbits 6
> +static const float LUT_dequantization_mul[LUT_dequantization_maxbits] = { 1.0, 2.0, 4.0, 8.0, 16.0, 64.0 };
> +static float LUT_dequantization_add[LUT_dequantization_maxbits];
> +static int LUT_dequantization_size[LUT_dequantization_maxbits];
> +static uint8_t LUT_dequantization_table[LUT_dequantization_maxbits][1024];
static const float quant_lut_mul[6]={ 1.0, 2.0, 4.0, 8.0, 16.0, 64.0 };
static const float quant_lut_add[6]={123,345,678,...}
static const uint8_t quant_lut[1234]={
...
}
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
Democracy is the form of government in which you can choose your dictator
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