resample.c

mediastreamer2是开源的网络传输媒体流的库

   
   /* Per channel data */
   st->last_sample = (spx_int32_t*)speex_alloc(nb_channels*sizeof(int));
   st->magic_samples = (spx_uint32_t*)speex_alloc(nb_channels*sizeof(int));
   st->samp_frac_num = (spx_uint32_t*)speex_alloc(nb_channels*sizeof(int));
   for (i=0;i<nb_channels;i++)
   {
      st->last_sample[i] = 0;
      st->magic_samples[i] = 0;
      st->samp_frac_num[i] = 0;
   }

   speex_resampler_set_quality(st, quality);
   speex_resampler_set_rate_frac(st, ratio_num, ratio_den, in_rate, out_rate);

   
   update_filter(st);
   
   st->initialised = 1;
   if (err)
      *err = RESAMPLER_ERR_SUCCESS;

   return st;
}

EXPORT void speex_resampler_destroy(SpeexResamplerState *st)
{
   speex_free(st->mem);
   speex_free(st->sinc_table);
   speex_free(st->last_sample);
   speex_free(st->magic_samples);
   speex_free(st->samp_frac_num);
   speex_free(st);
}

static int speex_resampler_process_native(SpeexResamplerState *st, spx_uint32_t channel_index, spx_uint32_t *in_len, spx_word16_t *out, spx_uint32_t *out_len)
{
   int j=0;
   const int N = st->filt_len;
   int out_sample = 0;
   spx_word16_t *mem = st->mem + channel_index * st->mem_alloc_size;
   spx_uint32_t ilen;
   
   st->started = 1;
   
   /* Call the right resampler through the function ptr */
   out_sample = st->resampler_ptr(st, channel_index, mem, in_len, out, out_len);
   
   if (st->last_sample[channel_index] < (spx_int32_t)*in_len)
      *in_len = st->last_sample[channel_index];
   *out_len = out_sample;
   st->last_sample[channel_index] -= *in_len;
   
   ilen = *in_len;

   for(j=0;j<N-1;++j)
     mem[j] = mem[j+ilen];

   return RESAMPLER_ERR_SUCCESS;
}

static int speex_resampler_magic(SpeexResamplerState *st, spx_uint32_t channel_index, spx_word16_t **out, spx_uint32_t out_len) {
   spx_uint32_t tmp_in_len = st->magic_samples[channel_index];
   spx_word16_t *mem = st->mem + channel_index * st->mem_alloc_size;
   const int N = st->filt_len;
   
   speex_resampler_process_native(st, channel_index, &tmp_in_len, *out, &out_len);

   st->magic_samples[channel_index] -= tmp_in_len;
   
   /* If we couldn't process all "magic" input samples, save the rest for next time */
   if (st->magic_samples[channel_index])
   {
      spx_uint32_t i;
      for (i=0;i<st->magic_samples[channel_index];i++)
         mem[N-1+i]=mem[N-1+i+tmp_in_len];
   }
   *out += out_len*st->out_stride;
   return out_len;
}

#ifdef FIXED_POINT
EXPORT int speex_resampler_process_int(SpeexResamplerState *st, spx_uint32_t channel_index, const spx_int16_t *in, spx_uint32_t *in_len, spx_int16_t *out, spx_uint32_t *out_len)
#else
EXPORT int speex_resampler_process_float(SpeexResamplerState *st, spx_uint32_t channel_index, const float *in, spx_uint32_t *in_len, float *out, spx_uint32_t *out_len)
#endif
{
   int j;
   spx_uint32_t ilen = *in_len;
   spx_uint32_t olen = *out_len;
   spx_word16_t *x = st->mem + channel_index * st->mem_alloc_size;
   const int filt_offs = st->filt_len - 1;
   const spx_uint32_t xlen = st->mem_alloc_size - filt_offs;
   const int istride = st->in_stride;

   if (st->magic_samples[channel_index]) 
      olen -= speex_resampler_magic(st, channel_index, &out, olen);
   if (! st->magic_samples[channel_index]) {
      while (ilen && olen) {
        spx_uint32_t ichunk = (ilen > xlen) ? xlen : ilen;
        spx_uint32_t ochunk = olen;
 
        if (in) {
           for(j=0;j<ichunk;++j)
              x[j+filt_offs]=in[j*istride];
        } else {
          for(j=0;j<ichunk;++j)
            x[j+filt_offs]=0;
        }
        speex_resampler_process_native(st, channel_index, &ichunk, out, &ochunk);
        ilen -= ichunk;
        olen -= ochunk;
        out += ochunk * st->out_stride;
        if (in)
           in += ichunk * istride;
      }
   }
   *in_len -= ilen;
   *out_len -= olen;
   return RESAMPLER_ERR_SUCCESS;
}

#ifdef FIXED_POINT
EXPORT int speex_resampler_process_float(SpeexResamplerState *st, spx_uint32_t channel_index, const float *in, spx_uint32_t *in_len, float *out, spx_uint32_t *out_len)
#else
EXPORT int speex_resampler_process_int(SpeexResamplerState *st, spx_uint32_t channel_index, const spx_int16_t *in, spx_uint32_t *in_len, spx_int16_t *out, spx_uint32_t *out_len)
#endif
{
   int j;
   const int istride_save = st->in_stride;
   const int ostride_save = st->out_stride;
   spx_uint32_t ilen = *in_len;
   spx_uint32_t olen = *out_len;
   spx_word16_t *x = st->mem + channel_index * st->mem_alloc_size;
   const spx_uint32_t xlen = st->mem_alloc_size - (st->filt_len - 1);
#ifdef VAR_ARRAYS
   const unsigned int ylen = (olen < FIXED_STACK_ALLOC) ? olen : FIXED_STACK_ALLOC;
   VARDECL(spx_word16_t *ystack);
   ALLOC(ystack, ylen, spx_word16_t);
#else
   const unsigned int ylen = FIXED_STACK_ALLOC;
   spx_word16_t ystack[FIXED_STACK_ALLOC];
#endif

   st->out_stride = 1;
   
   while (ilen && olen) {
     spx_word16_t *y = ystack;
     spx_uint32_t ichunk = (ilen > xlen) ? xlen : ilen;
     spx_uint32_t ochunk = (olen > ylen) ? ylen : olen;
     spx_uint32_t omagic = 0;

     if (st->magic_samples[channel_index]) {
       omagic = speex_resampler_magic(st, channel_index, &y, ochunk);
       ochunk -= omagic;
       olen -= omagic;
     }
     if (! st->magic_samples[channel_index]) {
       if (in) {
         for(j=0;j<ichunk;++j)
#ifdef FIXED_POINT
           x[j+st->filt_len-1]=WORD2INT(in[j*istride_save]);
#else
           x[j+st->filt_len-1]=in[j*istride_save];
#endif
       } else {
         for(j=0;j<ichunk;++j)
           x[j+st->filt_len-1]=0;
       }

       speex_resampler_process_native(st, channel_index, &ichunk, y, &ochunk);
     } else {
       ichunk = 0;
       ochunk = 0;
     }

     for (j=0;j<ochunk+omagic;++j)
#ifdef FIXED_POINT
        out[j*ostride_save] = ystack[j];
#else
        out[j*ostride_save] = WORD2INT(ystack[j]);
#endif
     
     ilen -= ichunk;
     olen -= ochunk;
     out += (ochunk+omagic) * ostride_save;
     if (in)
       in += ichunk * istride_save;
   }
   st->out_stride = ostride_save;
   *in_len -= ilen;
   *out_len -= olen;

   return RESAMPLER_ERR_SUCCESS;
}

EXPORT int speex_resampler_process_interleaved_float(SpeexResamplerState *st, const float *in, spx_uint32_t *in_len, float *out, spx_uint32_t *out_len)
{
   spx_uint32_t i;
   int istride_save, ostride_save;
   spx_uint32_t bak_len = *out_len;
   istride_save = st->in_stride;
   ostride_save = st->out_stride;
   st->in_stride = st->out_stride = st->nb_channels;
   for (i=0;i<st->nb_channels;i++)
   {
      *out_len = bak_len;
      if (in != NULL)
         speex_resampler_process_float(st, i, in+i, in_len, out+i, out_len);
      else
         speex_resampler_process_float(st, i, NULL, in_len, out+i, out_len);
   }
   st->in_stride = istride_save;
   st->out_stride = ostride_save;
   return RESAMPLER_ERR_SUCCESS;
}
               
EXPORT int speex_resampler_process_interleaved_int(SpeexResamplerState *st, const spx_int16_t *in, spx_uint32_t *in_len, spx_int16_t *out, spx_uint32_t *out_len)
{
   spx_uint32_t i;
   int istride_save, ostride_save;
   spx_uint32_t bak_len = *out_len;
   istride_save = st->in_stride;
   ostride_save = st->out_stride;
   st->in_stride = st->out_stride = st->nb_channels;
   for (i=0;i<st->nb_channels;i++)
   {
      *out_len = bak_len;
      if (in != NULL)
         speex_resampler_process_int(st, i, in+i, in_len, out+i, out_len);
      else
         speex_resampler_process_int(st, i, NULL, in_len, out+i, out_len);
   }
   st->in_stride = istride_save;
   st->out_stride = ostride_save;
   return RESAMPLER_ERR_SUCCESS;
}

EXPORT int speex_resampler_set_rate(SpeexResamplerState *st, spx_uint32_t in_rate, spx_uint32_t out_rate)
{
   return speex_resampler_set_rate_frac(st, in_rate, out_rate, in_rate, out_rate);
}

EXPORT void speex_resampler_get_rate(SpeexResamplerState *st, spx_uint32_t *in_rate, spx_uint32_t *out_rate)
{
   *in_rate = st->in_rate;
   *out_rate = st->out_rate;
}

EXPORT int speex_resampler_set_rate_frac(SpeexResamplerState *st, spx_uint32_t ratio_num, spx_uint32_t ratio_den, spx_uint32_t in_rate, spx_uint32_t out_rate)
{
   spx_uint32_t fact;
   spx_uint32_t old_den;
   spx_uint32_t i;
   if (st->in_rate == in_rate && st->out_rate == out_rate && st->num_rate == ratio_num && st->den_rate == ratio_den)
      return RESAMPLER_ERR_SUCCESS;
   
   old_den = st->den_rate;
   st->in_rate = in_rate;
   st->out_rate = out_rate;
   st->num_rate = ratio_num;
   st->den_rate = ratio_den;
   /* FIXME: This is terribly inefficient, but who cares (at least for now)? */
   for (fact=2;fact<=IMIN(st->num_rate, st->den_rate);fact++)
   {
      while ((st->num_rate % fact == 0) && (st->den_rate % fact == 0))
      {
         st->num_rate /= fact;
         st->den_rate /= fact;
      }
   }
      
   if (old_den > 0)
   {
      for (i=0;i<st->nb_channels;i++)
      {
         st->samp_frac_num[i]=st->samp_frac_num[i]*st->den_rate/old_den;
         /* Safety net */
         if (st->samp_frac_num[i] >= st->den_rate)
            st->samp_frac_num[i] = st->den_rate-1;
      }
   }
   
   if (st->initialised)
      update_filter(st);
   return RESAMPLER_ERR_SUCCESS;
}

EXPORT void speex_resampler_get_ratio(SpeexResamplerState *st, spx_uint32_t *ratio_num, spx_uint32_t *ratio_den)
{
   *ratio_num = st->num_rate;
   *ratio_den = st->den_rate;
}

EXPORT int speex_resampler_set_quality(SpeexResamplerState *st, int quality)
{
   if (quality > 10 || quality < 0)
      return RESAMPLER_ERR_INVALID_ARG;
   if (st->quality == quality)
      return RESAMPLER_ERR_SUCCESS;
   st->quality = quality;
   if (st->initialised)
      update_filter(st);
   return RESAMPLER_ERR_SUCCESS;
}

EXPORT void speex_resampler_get_quality(SpeexResamplerState *st, int *quality)
{
   *quality = st->quality;
}

EXPORT void speex_resampler_set_input_stride(SpeexResamplerState *st, spx_uint32_t stride)
{
   st->in_stride = stride;
}

EXPORT void speex_resampler_get_input_stride(SpeexResamplerState *st, spx_uint32_t *stride)
{
   *stride = st->in_stride;
}

EXPORT void speex_resampler_set_output_stride(SpeexResamplerState *st, spx_uint32_t stride)
{
   st->out_stride = stride;
}

EXPORT void speex_resampler_get_output_stride(SpeexResamplerState *st, spx_uint32_t *stride)
{
   *stride = st->out_stride;
}

EXPORT int speex_resampler_get_input_latency(SpeexResamplerState *st)
{
  return st->filt_len / 2;
}

EXPORT int speex_resampler_get_output_latency(SpeexResamplerState *st)
{
  return ((st->filt_len / 2) * st->den_rate + (st->num_rate >> 1)) / st->num_rate;
}

EXPORT int speex_resampler_skip_zeros(SpeexResamplerState *st)
{
   spx_uint32_t i;
   for (i=0;i<st->nb_channels;i++)
      st->last_sample[i] = st->filt_len/2;
   return RESAMPLER_ERR_SUCCESS;
}

EXPORT int speex_resampler_reset_mem(SpeexResamplerState *st)
{
   spx_uint32_t i;
   for (i=0;i<st->nb_channels*(st->filt_len-1);i++)
      st->mem[i] = 0;
   return RESAMPLER_ERR_SUCCESS;
}

EXPORT const char *speex_resampler_strerror(int err)
{
   switch (err)
   {
      case RESAMPLER_ERR_SUCCESS:
         return "Success.";
      case RESAMPLER_ERR_ALLOC_FAILED:
         return "Memory allocation failed.";
      case RESAMPLER_ERR_BAD_STATE:
         return "Bad resampler state.";
      case RESAMPLER_ERR_INVALID_ARG:
         return "Invalid argument.";
      case RESAMPLER_ERR_PTR_OVERLAP:
         return "Input and output buffers overlap.";
      default:
         return "Unknown error. Bad error code or strange version mismatch.";
   }
}