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resampler: Refactor calc_map_table()

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- Separate the cases with PA_RESAMPLER_NO_REMAP or PA_RESAMPLER_NO_REMIX
  set and remove redundant if-conditions.
- Fix C90 compiler warning due to mixing code and variable declaration.
- Do not repeatedly count number of left, right and center channels in
  the input channel map.

The logic of calc_map_table() remains unaltered.
This commit is contained in:
Stefan Huber 2013-02-07 14:03:16 +01:00 • committed by Tanu Kaskinen
parent 8f009c8680
commit 1a40af9c3b
1 changed files with 198 additions and 223 deletions
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421
src/pulsecore/resampler.c
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@ -668,229 +668,207 @@ static void calc_map_table(pa_resampler *r) {
memset(m->map_table_i, 0, sizeof(m->map_table_i));
memset(ic_connected, 0, sizeof(ic_connected));
remix = (r->flags & (PA_RESAMPLER_NO_REMAP|PA_RESAMPLER_NO_REMIX)) == 0;
remix = (r->flags & (PA_RESAMPLER_NO_REMAP | PA_RESAMPLER_NO_REMIX)) == 0;
for (oc = 0; oc < n_oc; oc++) {
bool oc_connected = false;
pa_channel_position_t b = r->o_cm.map[oc];
if (r->flags & PA_RESAMPLER_NO_REMAP) {
pa_assert(!remix);
for (ic = 0; ic < n_ic; ic++) {
pa_channel_position_t a = r->i_cm.map[ic];
for (oc = 0; oc < PA_MIN(n_ic, n_oc); oc++)
m->map_table_f[oc][oc] = 1.0f;
if (r->flags & PA_RESAMPLER_NO_REMAP) {
/* We shall not do any remapping. Hence, just check by index */
} else if (r->flags & PA_RESAMPLER_NO_REMIX) {
pa_assert(!remix);
for (oc = 0; oc < n_oc; oc++) {
pa_channel_position_t b = r->o_cm.map[oc];
if (ic == oc)
m->map_table_f[oc][ic] = 1.0;
for (ic = 0; ic < n_ic; ic++) {
pa_channel_position_t a = r->i_cm.map[ic];
continue;
}
if (r->flags & PA_RESAMPLER_NO_REMIX) {
/* We shall not do any remixing. Hence, just check by name */
if (a == b)
m->map_table_f[oc][ic] = 1.0;
continue;
}
pa_assert(remix);
/* OK, we shall do the full monty: upmixing and
* downmixing. Our algorithm is relatively simple, does
* not do spacialization, delay elements or apply lowpass
* filters for LFE. Patches are always welcome,
* though. Oh, and it doesn't do any matrix
* decoding. (Which probably wouldn't make any sense
* anyway.)
*
* This code is not idempotent: downmixing an upmixed
* stereo stream is not identical to the original. The
* volume will not match, and the two channels will be a
* linear combination of both.
*
* This is loosely based on random suggestions found on the
* Internet, such as this:
* http://www.halfgaar.net/surround-sound-in-linux and the
* alsa upmix plugin.
*
* The algorithm works basically like this:
*
* 1) Connect all channels with matching names.
*
* 2) Mono Handling:
* S:Mono: Copy into all D:channels
* D:Mono: Avg all S:channels
*
* 3) Mix D:Left, D:Right:
* D:Left: If not connected, avg all S:Left
* D:Right: If not connected, avg all S:Right
*
* 4) Mix D:Center
* If not connected, avg all S:Center
* If still not connected, avg all S:Left, S:Right
*
* 5) Mix D:LFE
* If not connected, avg all S:*
*
* 6) Make sure S:Left/S:Right is used: S:Left/S:Right: If
* not connected, mix into all D:left and all D:right
* channels. Gain is 0.1, the current left and right
* should be multiplied by 0.9.
*
* 7) Make sure S:Center, S:LFE is used:
*
* S:Center, S:LFE: If not connected, mix into all
* D:left, all D:right, all D:center channels, gain is
* 0.375. The current (as result of 1..6) factors
* should be multiplied by 0.75. (Alt. suggestion: 0.25
* vs. 0.5) If C-front is only mixed into
* L-front/R-front if available, otherwise into all L/R
* channels. Similarly for C-rear.
*
* S: and D: shall relate to the source resp. destination channels.
*
* Rationale: 1, 2 are probably obvious. For 3: this
* copies front to rear if needed. For 4: we try to find
* some suitable C source for C, if we don't find any, we
* avg L and R. For 5: LFE is mixed from all channels. For
* 6: the rear channels should not be dropped entirely,
* however have only minimal impact. For 7: movies usually
* encode speech on the center channel. Thus we have to
* make sure this channel is distributed to L and R if not
* available in the output. Also, LFE is used to achieve a
* greater dynamic range, and thus we should try to do our
* best to pass it to L+R.
*/
if (a == b || a == PA_CHANNEL_POSITION_MONO) {
m->map_table_f[oc][ic] = 1.0;
oc_connected = true;
ic_connected[ic] = true;
}
else if (b == PA_CHANNEL_POSITION_MONO) {
if (n_ic)
m->map_table_f[oc][ic] = 1.0f / (float) n_ic;
oc_connected = true;
ic_connected[ic] = true;
m->map_table_f[oc][ic] = 1.0f;
}
}
} else {
if (!oc_connected && remix) {
/* OK, we shall remix */
/* OK, we shall do the full monty: upmixing and downmixing. Our
* algorithm is relatively simple, does not do spacialization, delay
* elements or apply lowpass filters for LFE. Patches are always
* welcome, though. Oh, and it doesn't do any matrix decoding. (Which
* probably wouldn't make any sense anyway.)
*
* This code is not idempotent: downmixing an upmixed stereo stream is
* not identical to the original. The volume will not match, and the
* two channels will be a linear combination of both.
*
* This is loosely based on random suggestions found on the Internet,
* such as this:
* http://www.halfgaar.net/surround-sound-in-linux and the alsa upmix
* plugin.
*
* The algorithm works basically like this:
*
* 1) Connect all channels with matching names.
*
* 2) Mono Handling:
* S:Mono: Copy into all D:channels
* D:Mono: Avg all S:channels
*
* 3) Mix D:Left, D:Right:
* D:Left: If not connected, avg all S:Left
* D:Right: If not connected, avg all S:Right
*
* 4) Mix D:Center
* If not connected, avg all S:Center
* If still not connected, avg all S:Left, S:Right
*
* 5) Mix D:LFE
* If not connected, avg all S:*
*
* 6) Make sure S:Left/S:Right is used: S:Left/S:Right: If not
* connected, mix into all D:left and all D:right channels. Gain is
* 0.1, the current left and right should be multiplied by 0.9.
*
* 7) Make sure S:Center, S:LFE is used:
*
* S:Center, S:LFE: If not connected, mix into all D:left, all
* D:right, all D:center channels, gain is 0.375. The current (as
* result of 1..6) factors should be multiplied by 0.75. (Alt.
* suggestion: 0.25 vs. 0.5) If C-front is only mixed into
* L-front/R-front if available, otherwise into all L/R channels.
* Similarly for C-rear.
*
* S: and D: shall relate to the source resp. destination channels.
*
* Rationale: 1, 2 are probably obvious. For 3: this copies front to
* rear if needed. For 4: we try to find some suitable C source for C,
* if we don't find any, we avg L and R. For 5: LFE is mixed from all
* channels. For 6: the rear channels should not be dropped entirely,
* however have only minimal impact. For 7: movies usually encode
* speech on the center channel. Thus we have to make sure this channel
* is distributed to L and R if not available in the output. Also, LFE
* is used to achieve a greater dynamic range, and thus we should try
* to do our best to pass it to L+R.
*/
/* Try to find matching input ports for this output port */
if (on_left(b)) {
unsigned n = 0;
/* We are not connected and on the left side, let's
* average all left side input channels. */
for (ic = 0; ic < n_ic; ic++)
if (on_left(r->i_cm.map[ic]))
n++;
if (n > 0)
for (ic = 0; ic < n_ic; ic++)
if (on_left(r->i_cm.map[ic])) {
m->map_table_f[oc][ic] = 1.0f / (float) n;
ic_connected[ic] = true;
}
/* We ignore the case where there is no left input
* channel. Something is really wrong in this case
* anyway. */
} else if (on_right(b)) {
unsigned n = 0;
/* We are not connected and on the right side, let's
* average all right side input channels. */
for (ic = 0; ic < n_ic; ic++)
if (on_right(r->i_cm.map[ic]))
n++;
if (n > 0)
for (ic = 0; ic < n_ic; ic++)
if (on_right(r->i_cm.map[ic])) {
m->map_table_f[oc][ic] = 1.0f / (float) n;
ic_connected[ic] = true;
}
/* We ignore the case where there is no right input
* channel. Something is really wrong in this case
* anyway. */
} else if (on_center(b)) {
unsigned n = 0;
/* We are not connected and at the center. Let's
* average all center input channels. */
for (ic = 0; ic < n_ic; ic++)
if (on_center(r->i_cm.map[ic]))
n++;
if (n > 0) {
for (ic = 0; ic < n_ic; ic++)
if (on_center(r->i_cm.map[ic])) {
m->map_table_f[oc][ic] = 1.0f / (float) n;
ic_connected[ic] = true;
}
} else {
/* Hmm, no center channel around, let's synthesize
* it by mixing L and R.*/
n = 0;
for (ic = 0; ic < n_ic; ic++)
if (on_left(r->i_cm.map[ic]) || on_right(r->i_cm.map[ic]))
n++;
if (n > 0)
for (ic = 0; ic < n_ic; ic++)
if (on_left(r->i_cm.map[ic]) || on_right(r->i_cm.map[ic])) {
m->map_table_f[oc][ic] = 1.0f / (float) n;
ic_connected[ic] = true;
}
/* We ignore the case where there is not even a
* left or right input channel. Something is
* really wrong in this case anyway. */
}
} else if (on_lfe(b)) {
/* We are not connected and an LFE. Let's average all
* channels for LFE. */
for (ic = 0; ic < n_ic; ic++) {
if (!(r->flags & PA_RESAMPLER_NO_LFE))
m->map_table_f[oc][ic] = 1.0f / (float) n_ic;
else
m->map_table_f[oc][ic] = 0;
/* Please note that a channel connected to LFE
* doesn't really count as connected. */
}
}
}
}
if (remix) {
unsigned
ic_left = 0,
ic_right = 0,
ic_center = 0,
ic_unconnected_left = 0,
ic_unconnected_right = 0,
ic_unconnected_center = 0,
ic_unconnected_lfe = 0;
pa_assert(remix);
for (ic = 0; ic < n_ic; ic++) {
if (on_left(r->i_cm.map[ic]))
ic_left++;
if (on_right(r->i_cm.map[ic]))
ic_right++;
if (on_center(r->i_cm.map[ic]))
ic_center++;
}
for (oc = 0; oc < n_oc; oc++) {
bool oc_connected = false;
pa_channel_position_t b = r->o_cm.map[oc];
for (ic = 0; ic < n_ic; ic++) {
pa_channel_position_t a = r->i_cm.map[ic];
if (a == b || a == PA_CHANNEL_POSITION_MONO) {
m->map_table_f[oc][ic] = 1.0f;
oc_connected = true;
ic_connected[ic] = true;
}
else if (b == PA_CHANNEL_POSITION_MONO) {
m->map_table_f[oc][ic] = 1.0f / (float) n_ic;
oc_connected = true;
ic_connected[ic] = true;
}
}
if (!oc_connected) {
/* Try to find matching input ports for this output port */
if (on_left(b)) {
/* We are not connected and on the left side, let's
* average all left side input channels. */
if (ic_left > 0)
for (ic = 0; ic < n_ic; ic++)
if (on_left(r->i_cm.map[ic])) {
m->map_table_f[oc][ic] = 1.0f / (float) ic_left;
ic_connected[ic] = true;
}
/* We ignore the case where there is no left input channel.
* Something is really wrong in this case anyway. */
} else if (on_right(b)) {
/* We are not connected and on the right side, let's
* average all right side input channels. */
if (ic_right > 0)
for (ic = 0; ic < n_ic; ic++)
if (on_right(r->i_cm.map[ic])) {
m->map_table_f[oc][ic] = 1.0f / (float) ic_right;
ic_connected[ic] = true;
}
/* We ignore the case where there is no right input
* channel. Something is really wrong in this case anyway.
* */
} else if (on_center(b)) {
if (ic_center > 0) {
/* We are not connected and at the center. Let's average
* all center input channels. */
for (ic = 0; ic < n_ic; ic++)
if (on_center(r->i_cm.map[ic])) {
m->map_table_f[oc][ic] = 1.0f / (float) ic_center;
ic_connected[ic] = true;
}
} else if (ic_left + ic_right > 0) {
/* Hmm, no center channel around, let's synthesize it
* by mixing L and R.*/
for (ic = 0; ic < n_ic; ic++)
if (on_left(r->i_cm.map[ic]) || on_right(r->i_cm.map[ic])) {
m->map_table_f[oc][ic] = 1.0f / (float) (ic_left + ic_right);
ic_connected[ic] = true;
}
}
/* We ignore the case where there is not even a left or
* right input channel. Something is really wrong in this
* case anyway. */
} else if (on_lfe(b) && !(r->flags & PA_RESAMPLER_NO_LFE)) {
/* We are not connected and an LFE. Let's average all
* channels for LFE. */
for (ic = 0; ic < n_ic; ic++)
m->map_table_f[oc][ic] = 1.0f / (float) n_ic;
/* Please note that a channel connected to LFE doesn't
* really count as connected. */
}
}
}
for (ic = 0; ic < n_ic; ic++) {
pa_channel_position_t a = r->i_cm.map[ic];
@ -909,10 +887,9 @@ static void calc_map_table(pa_resampler *r) {
if (ic_unconnected_left > 0) {
/* OK, so there are unconnected input channels on the
* left. Let's multiply all already connected channels on
* the left side by .9 and add in our averaged unconnected
* channels multiplied by .1 */
/* OK, so there are unconnected input channels on the left. Let's
* multiply all already connected channels on the left side by .9
* and add in our averaged unconnected channels multiplied by .1 */
for (oc = 0; oc < n_oc; oc++) {
@ -934,10 +911,9 @@ static void calc_map_table(pa_resampler *r) {
if (ic_unconnected_right > 0) {
/* OK, so there are unconnected input channels on the
* right. Let's multiply all already connected channels on
* the right side by .9 and add in our averaged unconnected
* channels multiplied by .1 */
/* OK, so there are unconnected input channels on the right. Let's
* multiply all already connected channels on the right side by .9
* and add in our averaged unconnected channels multiplied by .1 */
for (oc = 0; oc < n_oc; oc++) {
@ -960,10 +936,9 @@ static void calc_map_table(pa_resampler *r) {
if (ic_unconnected_center > 0) {
bool mixed_in = false;
/* OK, so there are unconnected input channels on the
* center. Let's multiply all already connected channels on
* the center side by .9 and add in our averaged unconnected
* channels multiplied by .1 */
/* OK, so there are unconnected input channels on the center. Let's
* multiply all already connected channels on the center side by .9
* and add in our averaged unconnected channels multiplied by .1 */
for (oc = 0; oc < n_oc; oc++) {
@ -992,9 +967,8 @@ static void calc_map_table(pa_resampler *r) {
memset(found_frs, 0, sizeof(found_frs));
/* Hmm, as it appears there was no center channel we
could mix our center channel in. In this case, mix
it into left and right. Using .375 and 0.75 as
factors. */
could mix our center channel in. In this case, mix it into
left and right. Using .375 and 0.75 as factors. */
for (ic = 0; ic < n_ic; ic++) {
@ -1052,8 +1026,8 @@ static void calc_map_table(pa_resampler *r) {
if (ic_unconnected_lfe > 0 && !(r->flags & PA_RESAMPLER_NO_LFE)) {
/* OK, so there is an unconnected LFE channel. Let's mix
* it into all channels, with factor 0.375 */
/* OK, so there is an unconnected LFE channel. Let's mix it into
* all channels, with factor 0.375 */
for (ic = 0; ic < n_ic; ic++) {
@ -1065,6 +1039,7 @@ static void calc_map_table(pa_resampler *r) {
}
}
}
/* make an 16:16 int version of the matrix */
for (oc = 0; oc < n_oc; oc++)
for (ic = 0; ic < n_ic; ic++)