gboolean
audio_convert_prepare_context (AudioConvertCtx * ctx, AudioConvertFmt * in,
AudioConvertFmt * out, GstAudioConvertDithering dither,
GstAudioConvertNoiseShaping ns)
{
gint idx_in, idx_out;
g_return_val_if_fail (ctx != NULL, FALSE);
g_return_val_if_fail (in != NULL, FALSE);
g_return_val_if_fail (out != NULL, FALSE);
/* first clean the existing context */
audio_convert_clean_context (ctx);
g_return_val_if_fail (in->unpositioned_layout == out->unpositioned_layout,
FALSE);
ctx->in = *in;
ctx->out = *out;
/* Don't dither or apply noise shaping if target depth is bigger than 20 bits
* as DA converters only can do a SNR up to 20 bits in reality.
* Also don't dither or apply noise shaping if target depth is larger than
* source depth. */
if (ctx->out.depth <= 20 && (!ctx->in.is_int
|| ctx->in.depth >= ctx->out.depth)) {
ctx->dither = dither;
ctx->ns = ns;
} else {
ctx->dither = DITHER_NONE;
ctx->ns = NOISE_SHAPING_NONE;
}
/* Use simple error feedback when output sample rate is smaller than
* 32000 as the other methods might move the noise to audible ranges */
if (ctx->ns > NOISE_SHAPING_ERROR_FEEDBACK && ctx->out.rate < 32000)
ctx->ns = NOISE_SHAPING_ERROR_FEEDBACK;
gst_channel_mix_setup_matrix (ctx);
idx_in = audio_convert_get_func_index (ctx, in);
ctx->unpack = unpack_funcs[idx_in];
idx_out = audio_convert_get_func_index (ctx, out);
ctx->pack = pack_funcs[idx_out];
/* if both formats are float/double or we use noise shaping use double as
* intermediate format and and switch mixing */
if (!DOUBLE_INTERMEDIATE_FORMAT (ctx)) {
GST_INFO ("use int mixing");
ctx->channel_mix = (AudioConvertMix) gst_channel_mix_mix_int;
} else {
GST_INFO ("use float mixing");
ctx->channel_mix = (AudioConvertMix) gst_channel_mix_mix_float;
}
GST_INFO ("unitsizes: %d -> %d", in->unit_size, out->unit_size);
/* check if input is in default format */
ctx->in_default = check_default (ctx, in);
/* check if channel mixer is passthrough */
ctx->mix_passthrough = gst_channel_mix_passthrough (ctx);
/* check if output is in default format */
ctx->out_default = check_default (ctx, out);
GST_INFO ("in default %d, mix passthrough %d, out default %d",
ctx->in_default, ctx->mix_passthrough, ctx->out_default);
ctx->in_scale = (in->is_int) ? (32 - in->depth) : 0;
ctx->out_scale = (out->is_int) ? (32 - out->depth) : 0;
gst_audio_quantize_setup (ctx);
return TRUE;
}
gboolean
audio_convert_prepare_context (AudioConvertCtx * ctx, GstAudioInfo * in,
GstAudioInfo * out, GstAudioConvertDithering dither,
GstAudioConvertNoiseShaping ns)
{
gint idx_in, idx_out;
gint in_depth, out_depth;
g_return_val_if_fail (ctx != NULL, FALSE);
g_return_val_if_fail (in != NULL, FALSE);
g_return_val_if_fail (out != NULL, FALSE);
/* first clean the existing context */
audio_convert_clean_context (ctx);
if ((GST_AUDIO_INFO_CHANNELS (in) != GST_AUDIO_INFO_CHANNELS (out)) &&
(GST_AUDIO_INFO_IS_UNPOSITIONED (in)
|| GST_AUDIO_INFO_IS_UNPOSITIONED (out)))
goto unpositioned;
ctx->in = *in;
ctx->out = *out;
in_depth = GST_AUDIO_FORMAT_INFO_DEPTH (in->finfo);
out_depth = GST_AUDIO_FORMAT_INFO_DEPTH (out->finfo);
GST_INFO ("depth in %d, out %d", in_depth, out_depth);
/* Don't dither or apply noise shaping if target depth is bigger than 20 bits
* as DA converters only can do a SNR up to 20 bits in reality.
* Also don't dither or apply noise shaping if target depth is larger than
* source depth. */
if (out_depth <= 20 && (!GST_AUDIO_FORMAT_INFO_IS_INTEGER (in->finfo)
|| in_depth >= out_depth)) {
ctx->dither = dither;
ctx->ns = ns;
GST_INFO ("using dither %d and noise shaping %d", dither, ns);
} else {
ctx->dither = DITHER_NONE;
ctx->ns = NOISE_SHAPING_NONE;
GST_INFO ("using no dither and noise shaping");
}
/* Use simple error feedback when output sample rate is smaller than
* 32000 as the other methods might move the noise to audible ranges */
if (ctx->ns > NOISE_SHAPING_ERROR_FEEDBACK && out->rate < 32000)
ctx->ns = NOISE_SHAPING_ERROR_FEEDBACK;
gst_channel_mix_setup_matrix (ctx);
idx_in = audio_convert_get_func_index (ctx, in->finfo);
ctx->unpack = unpack_funcs[idx_in];
idx_out = audio_convert_get_func_index (ctx, out->finfo);
ctx->pack = pack_funcs[idx_out];
GST_INFO ("func index in %d, out %d", idx_in, idx_out);
/* if both formats are float/double or we use noise shaping use double as
* intermediate format and switch mixing */
if (!DOUBLE_INTERMEDIATE_FORMAT (ctx)) {
GST_INFO ("use int mixing");
ctx->channel_mix = (AudioConvertMix) gst_channel_mix_mix_int;
} else {
GST_INFO ("use float mixing");
ctx->channel_mix = (AudioConvertMix) gst_channel_mix_mix_float;
}
GST_INFO ("unitsizes: %d -> %d", in->bpf, out->bpf);
/* check if input is in default format */
ctx->in_default = check_default (ctx, in->finfo);
/* check if channel mixer is passthrough */
ctx->mix_passthrough = gst_channel_mix_passthrough (ctx);
/* check if output is in default format */
ctx->out_default = check_default (ctx, out->finfo);
GST_INFO ("in default %d, mix passthrough %d, out default %d",
ctx->in_default, ctx->mix_passthrough, ctx->out_default);
ctx->in_scale =
GST_AUDIO_FORMAT_INFO_IS_INTEGER (in->finfo) ? (32 - in_depth) : 0;
ctx->out_scale =
GST_AUDIO_FORMAT_INFO_IS_INTEGER (out->finfo) ? (32 - out_depth) : 0;
GST_INFO ("scale in %d, out %d", ctx->in_scale, ctx->out_scale);
gst_audio_quantize_setup (ctx);
return TRUE;
/* ERRORS */
unpositioned:
{
GST_WARNING ("unpositioned channels");
return FALSE;
}
}
