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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(m->map_table_i, 0, sizeof(m->map_table_i));
memset(ic_connected, 0, sizeof(ic_connected)); 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++) { if (r->flags & PA_RESAMPLER_NO_REMAP) {
bool oc_connected = false; pa_assert(!remix);
pa_channel_position_t b = r->o_cm.map[oc];
for (ic = 0; ic < n_ic; ic++) { for (oc = 0; oc < PA_MIN(n_ic, n_oc); oc++)
pa_channel_position_t a = r->i_cm.map[ic]; m->map_table_f[oc][oc] = 1.0f;
if (r->flags & PA_RESAMPLER_NO_REMAP) { } else if (r->flags & PA_RESAMPLER_NO_REMIX) {
/* We shall not do any remapping. Hence, just check by index */ pa_assert(!remix);
for (oc = 0; oc < n_oc; oc++) {
pa_channel_position_t b = r->o_cm.map[oc];
if (ic == oc) for (ic = 0; ic < n_ic; ic++) {
m->map_table_f[oc][ic] = 1.0; 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 */ /* We shall not do any remixing. Hence, just check by name */
if (a == b) if (a == b)
m->map_table_f[oc][ic] = 1.0; m->map_table_f[oc][ic] = 1.0f;
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;
} }
} }
} else {
if (!oc_connected && remix) { /* OK, we shall do the full monty: upmixing and downmixing. Our
/* OK, we shall remix */ * 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 unsigned
ic_left = 0,
ic_right = 0,
ic_center = 0,
ic_unconnected_left = 0, ic_unconnected_left = 0,
ic_unconnected_right = 0, ic_unconnected_right = 0,
ic_unconnected_center = 0, ic_unconnected_center = 0,
ic_unconnected_lfe = 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++) { for (ic = 0; ic < n_ic; ic++) {
pa_channel_position_t a = r->i_cm.map[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) { if (ic_unconnected_left > 0) {
/* OK, so there are unconnected input channels on the /* OK, so there are unconnected input channels on the left. Let's
* left. Let's multiply all already connected channels on * multiply all already connected channels on the left side by .9
* the left side by .9 and add in our averaged unconnected * and add in our averaged unconnected channels multiplied by .1 */
* channels multiplied by .1 */
for (oc = 0; oc < n_oc; oc++) { for (oc = 0; oc < n_oc; oc++) {
@ -934,10 +911,9 @@ static void calc_map_table(pa_resampler *r) {
if (ic_unconnected_right > 0) { if (ic_unconnected_right > 0) {
/* OK, so there are unconnected input channels on the /* OK, so there are unconnected input channels on the right. Let's
* right. Let's multiply all already connected channels on * multiply all already connected channels on the right side by .9
* the right side by .9 and add in our averaged unconnected * and add in our averaged unconnected channels multiplied by .1 */
* channels multiplied by .1 */
for (oc = 0; oc < n_oc; oc++) { for (oc = 0; oc < n_oc; oc++) {
@ -960,10 +936,9 @@ static void calc_map_table(pa_resampler *r) {
if (ic_unconnected_center > 0) { if (ic_unconnected_center > 0) {
bool mixed_in = false; bool mixed_in = false;
/* OK, so there are unconnected input channels on the /* OK, so there are unconnected input channels on the center. Let's
* center. Let's multiply all already connected channels on * multiply all already connected channels on the center side by .9
* the center side by .9 and add in our averaged unconnected * and add in our averaged unconnected channels multiplied by .1 */
* channels multiplied by .1 */
for (oc = 0; oc < n_oc; oc++) { 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)); memset(found_frs, 0, sizeof(found_frs));
/* Hmm, as it appears there was no center channel we /* Hmm, as it appears there was no center channel we
could mix our center channel in. In this case, mix could mix our center channel in. In this case, mix it into
it into left and right. Using .375 and 0.75 as left and right. Using .375 and 0.75 as factors. */
factors. */
for (ic = 0; ic < n_ic; ic++) { 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)) { if (ic_unconnected_lfe > 0 && !(r->flags & PA_RESAMPLER_NO_LFE)) {
/* OK, so there is an unconnected LFE channel. Let's mix /* OK, so there is an unconnected LFE channel. Let's mix it into
* it into all channels, with factor 0.375 */ * all channels, with factor 0.375 */
for (ic = 0; ic < n_ic; ic++) { 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 */ /* make an 16:16 int version of the matrix */
for (oc = 0; oc < n_oc; oc++) for (oc = 0; oc < n_oc; oc++)
for (ic = 0; ic < n_ic; ic++) for (ic = 0; ic < n_ic; ic++)