[FFmpeg-devel] [PATCH] avfilter: add ambisonic decoder filter
Paul B Mahol
onemda at gmail.com
Sun Oct 30 20:19:03 EET 2022
On 10/30/22, James Almer <jamrial at gmail.com> wrote:
> On 10/30/2022 12:34 PM, Paul B Mahol wrote:
>> +static const struct {
>> + const int order;
>> + const int inputs;
>> + const int speakers;
>> + const int near_field;
>> + const int type;
>> + const double xover;
>> + const AVChannelLayout outlayout;
>> + const double *speakers_azimuth;
>> + const double *speakers_elevation;
>> + const double *speakers_distance;
>> +} ambisonic_tab[] = {
>> + [MONO] = {
>> + .order = 0,
>> + .inputs = 1,
>> + .speakers = 1,
>> + .near_field = NF_NONE,
>> + .xover = 0.,
>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_MONO,
>> + .speakers_azimuth = (const double[1]){ 0. },
>> + .speakers_distance = (const double[1]){ 1. },
>> + },
>> + [STEREO] = {
>> + .order = 1,
>> + .inputs = 4,
>> + .speakers = 2,
>> + .near_field = NF_NONE,
>> + .xover = 0.,
>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_STEREO,
>> + .speakers_azimuth = (const double[2]){ -30, 30},
>> + .speakers_distance = same_distance,
>> + },
>> + [STEREO_DOWNMIX] = {
>> + .order = 1,
>> + .inputs = 4,
>> + .speakers = 2,
>> + .near_field = NF_NONE,
>> + .xover = 0.,
>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_STEREO_DOWNMIX,
>> + .speakers_azimuth = (const double[2]){ -90, 90 },
>> + .speakers_distance = same_distance,
>> + },
>> + [SURROUND] = {
>> + .order = 1,
>> + .inputs = 4,
>> + .speakers = 3,
>> + .near_field = NF_NONE,
>> + .xover = 0.,
>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_SURROUND,
>> + .speakers_azimuth = (const double[3]){ -45, 45, 0 },
>> + .speakers_distance = same_distance,
>> + },
>> + [L2_1] = {
>> + .order = 1,
>> + .inputs = 4,
>> + .speakers = 3,
>> + .near_field = NF_NONE,
>> + .xover = 0.,
>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_2_1,
>> + .speakers_azimuth = (const double[3]){ -45, 45, 180 },
>> + .speakers_distance = same_distance,
>> + },
>> + [TRIANGLE] = {
>> + .order = 1,
>> + .inputs = 4,
>> + .speakers = 3,
>> + .type = 1,
>> + .near_field = NF_NONE,
>> + .xover = 0.,
>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_SURROUND,
>> + .speakers_azimuth = (const double[3]){ -120, 120, 0 },
>> + .speakers_distance = same_distance,
>> + },
>> + [QUAD] = {
>> + .order = 1,
>> + .inputs = 4,
>> + .speakers = 4,
>> + .near_field = NF_NONE,
>> + .xover = 0.,
>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_QUAD,
>> + .speakers_azimuth = (const double[4]){ -45, 45, -135, 135 },
>> + .speakers_distance = same_distance,
>> + },
>> + [SQUARE] = {
>> + .order = 1,
>> + .inputs = 4,
>> + .speakers = 4,
>> + .type = 1,
>> + .near_field = NF_NONE,
>> + .xover = 0.,
>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_4POINT0,
>> + .speakers_azimuth = (const double[4]){ 0, -90, 180, 90 },
>> + .speakers_distance = same_distance,
>> + },
>> + [L4_0] = {
>> + .order = 1,
>> + .inputs = 4,
>> + .speakers = 4,
>> + .near_field = NF_NONE,
>> + .xover = 0.,
>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_4POINT0,
>> + .speakers_azimuth = (const double[4]){ -30, 30, 0, 180 },
>> + .speakers_distance = same_distance,
>> + },
>> + [L5_0] = {
>> + .order = 1,
>> + .inputs = 4,
>> + .speakers = 5,
>> + .near_field = NF_NONE,
>> + .xover = 0.,
>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_5POINT0_BACK,
>> + .speakers_azimuth = (const double[5]){ -30, 30, 0, -145, 145 },
>> + .speakers_distance = same_distance,
>> + },
>> + [L5_0_SIDE] = {
>> + .order = 1,
>> + .inputs = 4,
>> + .speakers = 5,
>> + .near_field = NF_NONE,
>> + .xover = 0.,
>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_5POINT0,
>> + .speakers_azimuth = (const double[5]){ -30, 30, 0, -110, 110 },
>> + .speakers_distance = same_distance,
>> + },
>> + [L6_0] = {
>> + .order = 1,
>> + .inputs = 4,
>> + .speakers = 6,
>> + .near_field = NF_NONE,
>> + .xover = 0.,
>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_6POINT0,
>> + .speakers_azimuth = (const double[6]){ -30, 30, 0, 180, -110, 110
>> },
>> + .speakers_distance = same_distance,
>> + },
>> + [L7_0] = {
>> + .order = 1,
>> + .inputs = 4,
>> + .speakers = 7,
>> + .near_field = NF_NONE,
>> + .xover = 0.,
>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_7POINT0,
>> + .speakers_azimuth = (const double[7]){ -30, 30, 0, -145, 145,
>> -110, 110 },
>> + .speakers_distance = same_distance,
>> + },
>> + [TETRA] = {
>> + .order = 1,
>> + .inputs = 4,
>> + .speakers = 4,
>> + .type = 2,
>> + .near_field = NF_NONE,
>> + .xover = 0.,
>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_QUAD,
>> + .speakers_azimuth = (const double[4]){ -90, 90, 0, 180 },
>> + .speakers_elevation = (const double[4]){ -35.3, -35.3, 35.3, 35.3
>> },
>> + .speakers_distance = same_distance,
>> + },
>> + [CUBE] = {
>> + .order = 1,
>> + .inputs = 4,
>> + .speakers = 8,
>> + .type = 2,
>> + .near_field = NF_NONE,
>> + .xover = 0.,
>> + .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_7POINT1,
>
> 7.1 defines an LFE channel, which is clearly not intended here, so it
> should be either:
>
> .outlayout = (AVChannelLayout)AV_CHANNEL_LAYOUT_MASK(8,
> AV_CH_LAYOUT_QUAD |
> AV_CH_TOP_FRONT_LEFT |
> AV_CH_TOP_FRONT_RIGHT |
> AV_CH_TOP_BACK_LEFT |
> AV_CH_TOP_BACK_RIGHT),
>
> Or the AV_CHANNEL_LAYOUT_CUBE layout (using the exact same bitmask as
> above) after the patch i sent just now is committed.
CUBE is as real cube in 3d space. No current layout in API can be
described correctly.
>
>> + .speakers_azimuth = cube_azimuth,
>> + .speakers_elevation = cube_elevation,
>> + .speakers_distance = same_distance,
>> + },
>
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