mal_bool32 isPassthrough : 1; // <-- Will be set to true when the DSP pipeline is an optimized passthrough.
mal_bool32 isPassthrough : 1; // <-- Will be set to true when the DSP pipeline is an optimized passthrough.
mal_channel channelMapInPostMix[MAL_MAX_CHANNELS]; // <-- When mixing, new channels may need to be created. This represents the channel map after mixing.
// There are two main things you can do with the channel router:
// 1) Rearrange channels
// 2) Convert from one channel count to another
//
//
// Note that currently the channel router requires input data to be deinterleaved. Also, it currently only supports
// Channel Rearrangement
// deinterleaved output. If you need interleaving you need to run samples through a format converter.
// ---------------------
// A simple example of channel rearrangement may be swapping the left and right channels in a stereo stream. To do this you just pass in the same channel
// count for both the input and output with channel maps that contain the same channels (in a different order).
// The channel router can also convert from one channel count to another, such as converting a 5.1 stream to stero. When changing the channel count, the
// router will first perform a 1:1 mapping of channel positions that are present in both the input and output channel maps. The second thing it will do
// is distribute the input mono channel (if any) across all output channels, excluding any None and LFE channels. If there is an output mono channel, all
// input channels will be averaged, excluding any None and LFE channels.
//
// The last case to consider is when a channel position in the input channel map is not present in the output channel map, and vice versa. In this case the
// channel router will perform a blend of other related channels to produce an audible channel. There are several blending modes.
// 1) Simple
// Unmatched channels are ignored.
// 2) Planar Blending
// Channels are blended based on a set of planes that each speaker emits audio from.
//
// Planar Blending
// ---------------
// In this mode, channel positions are associated with a set of planes where the channel conceptually emits audio from. An example is the front/left speaker.
// This speaker is positioned to the front of the listener, so you can think of it as emitting audio from the front plane. It is also positioned to the left
// of the listener so you can think of it as also emitting audio from the left plane. Now consider the (unrealistic) situation where the input channel map
// contains only the front/left channel position, but the output channel map contains both the front/left and front/center channel. When deciding on the audio
// data to send to the front/center speaker (which has no 1:1 mapping with an input channel) we need to use some logic based on our available input channel
// positions.
//
// As mentioned earlier, our front/left speaker is, conceptually speaking, emitting audio from the front _and_ the left planes. Similarly, the front/center
// speaker is emitting audio from _only_ the front plane. What these two channels have in common is that they are both emitting audio from the front plane.
// Thus, it makes sense that the front/center speaker should receive some contribution from the front/left channel. How much contribution depends on their
// planar relationship (thus the name of this blending technique).
//
// Because the front/left channel is emitting audio from two planes (front and left), you can think of it as though it's willing to dedicate 50% of it's total
// volume to each of it's planes (a channel position emitting from 1 plane would be willing to given 100% of it's total volume to that plane, and a channel
// position emitting from 3 planes would be willing to given 33% of it's total volume to each plane). Similarly, the front/center speaker is emitting audio
// from only one plane so you can think of it as though it's willing to _take_ 100% of it's volume from front plane emissions. Now, since the front/left
// channel is willing to _give_ 50% of it's total volume to the front plane, and the front/center speaker is willing to _take_ 100% of it's total volume
// from the front, you can imagine that 50% of the front/left speaker will be given to the front/center speaker.
//
// This blending technique is not perfect, but it should provide a logical and reasonable estimate. This will not work well with speaker positions such as
// front/center/left (where the speaker is to the left of the front/center speaker) because the algorithm uses a simplified spatial model.
//
// Usage
// -----
// To use the channel router you need to specify three things:
// 1) The input channel count and channel map
// 2) The output channel count and channel map
// 3) The mixing mode to use in the case where a 1:1 mapping is unavailable
//
// Note that input and output data is always deinterleaved 32-bit floating point.
//
// Initialize the channel router with mal_channel_router_init(). You will need to pass in a config object which specifies the input and output configuration,
// mixing mode and a callback for sending data to the router. This callback will be called when input data needs to be sent to the router for processing.
//
// Read data from the channel router with mal_channel_router_read_deinterleaved(). Output data is always 32-bit floating point.
