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Add audio_peak and audio_magnitude support. (#85)
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‎README.md‎

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@@ -142,6 +142,10 @@ handle these variables being missing, but the shader may malfunction.)
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this to convert the UV coordinates of the pixel being processed to the coordinates of that texel in the source
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texture, or otherwise scale UV coordinate distances into texel distances.
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* **`prevous_output`** (`texture2d`)—The previous output of the filter (2.5.0)
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* **`audio_peak`** (`float`)—The instantaneous maximum audio level (peak) from the selected audio source, normalized to 0.0-1.0.
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More reactive to sudden sounds like drums.
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* **`audio_magnitude`** (`float`)—The RMS (Root Mean Square) audio level from the selected audio source, normalized to 0.0-1.0.
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Smoother representation of sustained audio levels.
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### Optional Preprocessing Macros
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@@ -165,6 +169,7 @@ I recommend *.shader* as they do not require `Use Effect File (.effect)` as pixe
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| animated_texture.effect | Animates a texture with polar sizing and color options | |
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| alpha-gaming-bent-camera.shader | | ![image](https://github.com/exeldro/obs-shaderfilter/assets/5457024/5fb6fec8-fc1b-46eb-96aa-17ce37a7ca20) |
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| ascii.shader | a little example of ascii art | ![image](https://github.com/exeldro/obs-shaderfilter/assets/5457024/682ad2d3-d32a-464e-a3af-0791ba0fc829) |
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| audio.shader | An example of a shader that reacts to real audio monitoring.
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| background_removal.effect | simple implementation of background removal. Optional color space corrections | |
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| blink.shader | A shader that fades the opacity of the output in and out over time, with a configurable speed multiplier. Demonstrates the user of the `elapsed_time` parameter. | |
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| bloom.shader | simple shaders to add bloom effects | ![image](https://github.com/exeldro/obs-shaderfilter/assets/5457024/567e5dc4-ec20-42fa-a344-2be1e6516b01) |

‎data/examples/audio.shader‎

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// Audio shader example showing the difference between audio_peak and audio_magnitude.
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// Left half uses audio_peak (red), right half uses audio_magnitude (blue).
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uniform float audio_peak;
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uniform float audio_magnitude;
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uniform float intensity <
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string label = "Audio intensity";
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string widget_type = "slider";
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float minimum = 0.1;
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float maximum = 3.0;
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float step = 0.1;
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> = 1.0;
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float4 mainImage(VertData v_in) : TARGET {
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float4 color = image.Sample(textureSampler, v_in.uv);
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// Split screen based on UV coordinate
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if (v_in.uv.x < 0.5) {
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// Left half: audio_peak (instantaneous spikes, more reactive)
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// Tint with red to show peak activity.
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float peak_strength = audio_peak * intensity;
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float3 peak_color = color.rgb + float3(peak_strength, 0, 0);
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return float4(peak_color, color.a);
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} else {
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// Right half: audio_magnitude (RMS/averaged levels, smoother)
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// Tint with blue to show magnitude activity.
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float mag_strength = audio_magnitude * intensity;
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float3 mag_color = color.rgb + float3(0, 0, mag_strength);
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return float4(mag_color, color.a);
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}
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}
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/*
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EXPLANATION:
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- audio_peak: Shows instantaneous maximum levels, very responsive to drums/percussion.
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- audio_magnitude: Shows RMS (Root Mean Square) levels, smoother and represents sustained audio.
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TYPICAL BEHAVIOR:
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- With music containing drums: Left side (peak) will flash more dramatically on beats.
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- With sustained tones: Right side (magnitude) will show more consistent levels.
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- Peak reacts faster to sudden sounds, magnitude is more stable for smooth effects.
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*/

‎obs-shaderfilter.c‎

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@@ -15,6 +15,7 @@
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#include <stdio.h>
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#include <time.h>
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#include <string.h>
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#include <math.h>
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#include <util/threading.h>
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#ifdef _WIN32
@@ -225,6 +226,8 @@ struct shader_filter_data {
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gs_eparam_t *param_transition_time;
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gs_eparam_t *param_convert_linear;
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gs_eparam_t *param_previous_output;
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gs_eparam_t *param_audio_peak;
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gs_eparam_t *param_audio_magnitude;
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int expand_left;
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int expand_right;
@@ -247,6 +250,13 @@ struct shader_filter_data {
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float rand_f;
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float rand_instance_f;
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float rand_activation_f;
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float audio_peak;
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float audio_magnitude;
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char *audio_source_name;
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obs_volmeter_t *volmeter;
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float current_audio_peak;
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float current_audio_magnitude;
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DARRAY(struct effect_param_data) stored_param_list;
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};
@@ -351,6 +361,8 @@ static void shader_filter_clear_params(struct shader_filter_data *filter)
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filter->param_loops = NULL;
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filter->param_loop_second = NULL;
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filter->param_local_time = NULL;
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filter->param_audio_peak = NULL;
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filter->param_audio_magnitude = NULL;
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filter->param_image = NULL;
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filter->param_previous_image = NULL;
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filter->param_image_a = NULL;
@@ -612,6 +624,10 @@ static void shader_filter_reload_effect(struct shader_filter_data *filter)
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filter->param_loop_second = param;
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} else if (strcmp(info.name, "local_time") == 0) {
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filter->param_local_time = param;
627+
} else if (strcmp(info.name, "audio_peak") == 0) {
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filter->param_audio_peak = param;
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} else if (strcmp(info.name, "audio_magnitude") == 0) {
630+
filter->param_audio_magnitude = param;
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} else if (strcmp(info.name, "ViewProj") == 0) {
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// Nothing.
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} else if (strcmp(info.name, "image") == 0) {
@@ -742,6 +758,11 @@ static void shader_filter_destroy(void *data)
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dstr_free(&filter->last_path);
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da_free(filter->stored_param_list);
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761+
if (filter->volmeter)
762+
obs_volmeter_destroy(filter->volmeter);
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if (filter->audio_source_name)
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bfree(filter->audio_source_name);
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745766
bfree(filter);
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}
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@@ -2097,6 +2118,53 @@ static bool shader_filter_convert(obs_properties_t *props, obs_property_t *prope
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static const char *shader_filter_texture_file_filter = "Textures (*.bmp *.tga *.png *.jpeg *.jpg *.gif);;";
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2121+
#define MIN_AUDIO_THRESHOLD -60.0f
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static float convert_db_to_linear(float db_value)
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{
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if (db_value <= MIN_AUDIO_THRESHOLD || db_value > 0.0f)
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return 0.0f;
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2128+
return fmaxf(0.0f, fminf(1.0f, (db_value - MIN_AUDIO_THRESHOLD) / (-MIN_AUDIO_THRESHOLD)));
2129+
}
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2131+
static void shader_filter_audio_callback(void *data, const float magnitude[MAX_AUDIO_CHANNELS],
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const float peak[MAX_AUDIO_CHANNELS], const float input_peak[MAX_AUDIO_CHANNELS])
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{
2134+
UNUSED_PARAMETER(input_peak);
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struct shader_filter_data *filter = (struct shader_filter_data *)data;
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2137+
float max_peak = MIN_AUDIO_THRESHOLD;
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for (int i = 0; i < MAX_AUDIO_CHANNELS; i++) {
2139+
if (peak[i] > max_peak && peak[i] != 0.0f) {
2140+
max_peak = peak[i];
2141+
}
2142+
}
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2144+
float max_magnitude = MIN_AUDIO_THRESHOLD;
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for (int i = 0; i < MAX_AUDIO_CHANNELS; i++) {
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if (magnitude[i] > max_magnitude && magnitude[i] != 0.0f) {
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max_magnitude = magnitude[i];
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}
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}
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2151+
filter->current_audio_peak = convert_db_to_linear(max_peak);
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filter->current_audio_magnitude = convert_db_to_linear(max_magnitude);
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}
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static bool shader_filter_enum_audio_sources(void *data, obs_source_t *source)
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{
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obs_property_t *prop = (obs_property_t *)data;
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uint32_t flags = obs_source_get_output_flags(source);
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2160+
if ((flags & OBS_SOURCE_AUDIO) != 0) {
2161+
const char *name = obs_source_get_name(source);
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obs_property_list_add_string(prop, name, name);
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}
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2165+
return true;
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}
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static obs_properties_t *shader_filter_properties(void *data)
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{
21022170
struct shader_filter_data *filter = data;
@@ -2150,6 +2218,14 @@ static obs_properties_t *shader_filter_properties(void *data)
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obs_properties_add_button(props, "reload_effect", obs_module_text("ShaderFilter.ReloadEffect"),
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shader_filter_reload_effect_clicked);
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2221+
if (filter && (filter->param_audio_magnitude || filter->param_audio_peak)) {
2222+
obs_property_t *audio_source = obs_properties_add_list(props, "audio_source", "Audio source", OBS_COMBO_TYPE_LIST,
2223+
OBS_COMBO_FORMAT_STRING);
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obs_property_list_add_string(audio_source, "None", "");
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2226+
obs_enum_sources(shader_filter_enum_audio_sources, audio_source);
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}
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21532229
DARRAY(obs_property_t *) groups;
21542230
da_init(groups);
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@@ -2393,6 +2469,56 @@ static void shader_filter_update(void *data, obs_data_t *settings)
23932469
obs_source_update_properties(filter->context);
23942470
}
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2472+
if (filter->param_audio_magnitude || filter->param_audio_peak) {
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const char *audio_source_name = obs_data_get_string(settings, "audio_source");
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if (!filter->audio_source_name || strcmp(filter->audio_source_name, audio_source_name) != 0) {
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obs_source_t *audio_source = strlen(audio_source_name) > 0 ? obs_get_source_by_name(audio_source_name) : NULL;
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if (audio_source && ((obs_source_get_output_flags(audio_source) & OBS_SOURCE_AUDIO) == 0)) {
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obs_source_release(audio_source);
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audio_source = NULL;
2479+
}
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if (audio_source) {
2481+
if (filter->audio_source_name)
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bfree(filter->audio_source_name);
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filter->audio_source_name = bstrdup(audio_source_name);
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}
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2486+
if (!audio_source) {
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audio_source = obs_source_get_ref(obs_filter_get_parent(filter->context));
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if (audio_source && ((obs_source_get_output_flags(audio_source) & OBS_SOURCE_AUDIO) == 0)) {
2489+
obs_source_release(audio_source);
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audio_source = NULL;
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}
2492+
}
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if (audio_source) {
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if (!filter->volmeter) {
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filter->volmeter = obs_volmeter_create(OBS_FADER_LOG);
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obs_volmeter_add_callback(filter->volmeter, shader_filter_audio_callback, filter);
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}
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obs_volmeter_attach_source(filter->volmeter, audio_source);
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obs_source_release(audio_source);
2500+
} else {
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if (filter->volmeter) {
2502+
obs_volmeter_destroy(filter->volmeter);
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filter->volmeter = NULL;
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}
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if (filter->audio_source_name) {
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bfree(filter->audio_source_name);
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filter->audio_source_name = NULL;
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}
2509+
}
2510+
}
2511+
} else {
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if (filter->volmeter) {
2513+
obs_volmeter_destroy(filter->volmeter);
2514+
filter->volmeter = NULL;
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}
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if (filter->audio_source_name) {
2517+
bfree(filter->audio_source_name);
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filter->audio_source_name = NULL;
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}
2520+
}
2521+
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size_t param_count = filter->stored_param_list.num;
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for (size_t param_index = 0; param_index < param_count; param_index++) {
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struct effect_param_data *param = (filter->stored_param_list.array + param_index);
@@ -2664,6 +2790,14 @@ static void shader_filter_tick(void *data, float seconds)
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// undecided between this and "rand_float(1);"
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filter->rand_f = (float)((double)rand_interval(0, 10000) / (double)10000);
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2793+
if (filter->volmeter) {
2794+
filter->audio_peak = filter->current_audio_peak;
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filter->audio_magnitude = filter->current_audio_magnitude;
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} else {
2797+
filter->audio_peak = 0.0f;
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filter->audio_magnitude = 0.0f;
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}
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26672801
filter->output_rendered = false;
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filter->input_rendered = false;
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}
@@ -2832,6 +2966,12 @@ void shader_filter_set_effect_params(struct shader_filter_data *filter)
28322966
if (filter->param_local_time != NULL) {
28332967
gs_effect_set_float(filter->param_local_time, filter->local_time);
28342968
}
2969+
if (filter->param_audio_peak != NULL) {
2970+
gs_effect_set_float(filter->param_audio_peak, filter->audio_peak);
2971+
}
2972+
if (filter->param_audio_magnitude != NULL) {
2973+
gs_effect_set_float(filter->param_audio_magnitude, filter->audio_magnitude);
2974+
}
28352975
if (filter->param_loops != NULL) {
28362976
gs_effect_set_int(filter->param_loops, filter->loops);
28372977
}

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