<html><head></head><body><div class="ydp407da3b7yahoo-style-wrap" style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:13px;"><div><div dir="ltr" data-setdir="false"><span>GstBuffer *bufferOut = gst_buffer_copy(buffer); </span></div><div><br></div><div class="ydp407da3b7signature"><div dir="ltr" data-setdir="false">you are making copy of the buffer adding the signal and the modifcation never gone to downstream.<br>Instead, map the buffer directly.<br><br></div><div><br></div><div>Sent from Yahoo Mail. <a href="https://yho.com/148vdq" rel="nofollow" target="_blank">Get the app</a></div></div></div>
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On Thursday, 9 March, 2023 at 05:46:34 am GMT-6, Sergei Hrushev via gstreamer-devel <gstreamer-devel@lists.freedesktop.org> wrote:
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<div><div dir="ltr">Hello Mr. Kesti!<br></div><div dir="ltr"><br></div><div dir="ltr">> Then it is something to do with the probe callback function. If you can post your your probe function may be I can help here/<br></div><div dir="ltr"><br></div><div dir="ltr">I prepared the complete example of a small app which modifies audio<br></div><div dir="ltr">frames directly in the BUFFER probe on the fly.<br></div><div dir="ltr"><br></div><div dir="ltr">In this app I'm adding probe to the CapsFilter 'src' pad - and the app<br></div><div dir="ltr">works as expected,<br></div><div dir="ltr">it properly overwrites the default signal with sine wave of different frequency.<br></div><div dir="ltr">(maybe there's a better way to determine amount of frames in the<br></div><div dir="ltr">current buffer?).<br></div><div dir="ltr"><br></div><div dir="ltr">Also in my real app when I'm adding similar probe for example to the<br></div><div dir="ltr">Tee 'src' pad - it also works.<br></div><div dir="ltr">But I need to use it on AudioAggregator 'src' pad - and there the<br></div><div dir="ltr">produced sound is "jammed".<br></div><div dir="ltr"><br></div><div dir="ltr">As in my case the entire audio pipeline works in Docker - I use<br></div><div dir="ltr">streaming to get the audio on host,<br></div><div dir="ltr">but it's easy to change the code to force it to play instead.<br></div><div dir="ltr">To play from streaming I'm using this:<br></div><div dir="ltr"><br></div><div dir="ltr">gst-launch-1.0 -v udpsrc port=50111 ! \<br></div><div dir="ltr"> application/x-rtp,media=audio,payload=96,encoding-name=OPUS,clock-rate=48000<br></div><div dir="ltr">! \<br></div><div dir="ltr"> rtpssrcdemux ! rtpopusdepay ! opusdec ! audioconvert ! audioresample<br></div><div dir="ltr">! queue ! autoaudiosink<br></div><div dir="ltr"><br></div><div dir="ltr">Best regards, Sergei Hrushev.<br></div><div dir="ltr"><br></div><div dir="ltr">-------- Code example -------<br></div><div dir="ltr"><br></div><div dir="ltr"><br></div><div dir="ltr">// Most of the boilerplate code is just a variation of code took from here:<br></div><div dir="ltr">// <a href="https://gstreamer.freedesktop.org/documentation/plugin-development/basics/testapp.html?gi-language=c" target="_blank">https://gstreamer.freedesktop.org/documentation/plugin-development/basics/testapp.html?gi-language=c</a><br></div><div dir="ltr"><br></div><div dir="ltr">#include <gst/gst.h><br></div><div dir="ltr"><br></div><div dir="ltr">#include <cmath><br></div><div dir="ltr">#include <string><br></div><div dir="ltr"><br></div><div dir="ltr">struct Storage {<br></div><div dir="ltr"> GMainLoop* loop;<br></div><div dir="ltr"> GstElement* pipeline;<br></div><div dir="ltr"> GstBus* bus;<br></div><div dir="ltr"> guint idWatch;<br></div><div dir="ltr"> GstElement* src1;<br></div><div dir="ltr"> GstElement* convert1;<br></div><div dir="ltr"> GstElement* resample1;<br></div><div dir="ltr"> GstElement* capsfilter1;<br></div><div dir="ltr"> gulong idProbe;<br></div><div dir="ltr"> GstElement* opusenc1;<br></div><div dir="ltr"> GstElement* rtpopuspay1;<br></div><div dir="ltr"> GstElement* udpsink1;<br></div><div dir="ltr"><br></div><div dir="ltr"> guint pos;<br></div><div dir="ltr">};<br></div><div dir="ltr"><br></div><div dir="ltr">static gboolean callbackBus(<br></div><div dir="ltr"> GstBus* bus,<br></div><div dir="ltr"> GstMessage* msg,<br></div><div dir="ltr"> gpointer data) {<br></div><div dir="ltr"><br></div><div dir="ltr"> GMainLoop* loop = static_cast<GMainLoop*>(data);<br></div><div dir="ltr"><br></div><div dir="ltr"> switch (GST_MESSAGE_TYPE (msg)) {<br></div><div dir="ltr"> case GST_MESSAGE_EOS:<br></div><div dir="ltr"> g_print ("End-of-stream\n");<br></div><div dir="ltr"> g_main_loop_quit (loop);<br></div><div dir="ltr"> break;<br></div><div dir="ltr"> case GST_MESSAGE_ERROR: {<br></div><div dir="ltr"> gchar* debug = NULL;<br></div><div dir="ltr"> GError* err = NULL;<br></div><div dir="ltr"><br></div><div dir="ltr"> gst_message_parse_error (msg, &err, &debug);<br></div><div dir="ltr"><br></div><div dir="ltr"> g_print ("Error: %s\n", err->message);<br></div><div dir="ltr"> g_error_free (err);<br></div><div dir="ltr"><br></div><div dir="ltr"> if (debug != nullptr) {<br></div><div dir="ltr"> g_print ("Debug details: %s\n", debug);<br></div><div dir="ltr"> g_free (debug);<br></div><div dir="ltr"> }<br></div><div dir="ltr"><br></div><div dir="ltr"> g_main_loop_quit (loop);<br></div><div dir="ltr"> break;<br></div><div dir="ltr"> }<br></div><div dir="ltr"> default:<br></div><div dir="ltr"> break;<br></div><div dir="ltr"> }<br></div><div dir="ltr"><br></div><div dir="ltr"> return TRUE;<br></div><div dir="ltr">}<br></div><div dir="ltr"><br></div><div dir="ltr">void generateSin(<br></div><div dir="ltr"> Storage* storage,<br></div><div dir="ltr"> int16_t* buf,<br></div><div dir="ltr"> int frequency,<br></div><div dir="ltr"> guint sampleRate,<br></div><div dir="ltr"> guint numChannels,<br></div><div dir="ltr"> guint numFrames) {<br></div><div dir="ltr"><br></div><div dir="ltr"> float valuePi = std::numbers::pi_v<float>;<br></div><div dir="ltr"><br></div><div dir="ltr"> // Amplitude<br></div><div dir="ltr"> int A = 16383; // 32767;<br></div><div dir="ltr"> // Frequency<br></div><div dir="ltr"> float freq = 1.0f * frequency;<br></div><div dir="ltr"><br></div><div dir="ltr"> float rate = 1.0f * sampleRate;<br></div><div dir="ltr"> float delta = 2 * valuePi / (rate / freq);<br></div><div dir="ltr"><br></div><div dir="ltr"> for(guint i = 0; i < numFrames; i++) {<br></div><div dir="ltr"> float angle = storage->pos * delta;<br></div><div dir="ltr"> int16_t v = static_cast<int16_t>(A * std::sin(angle));<br></div><div dir="ltr"><br></div><div dir="ltr"> for(guint ch = 0; ch < numChannels; ch++) {<br></div><div dir="ltr"> *(buf + i * numChannels + ch) = v;<br></div><div dir="ltr"> }<br></div><div dir="ltr"><br></div><div dir="ltr"> storage->pos++;<br></div><div dir="ltr"> storage->pos %= 48000;<br></div><div dir="ltr"> }<br></div><div dir="ltr">}<br></div><div dir="ltr"><br></div><div dir="ltr">GstPadProbeReturn probe(<br></div><div dir="ltr"> GstPad* pad,<br></div><div dir="ltr"> GstPadProbeInfo* info,<br></div><div dir="ltr"> gpointer user_data) {<br></div><div dir="ltr"><br></div><div dir="ltr"> Storage* storage = static_cast<Storage*>(user_data);<br></div><div dir="ltr"><br></div><div dir="ltr"> GstBuffer* buffer = GST_PAD_PROBE_INFO_BUFFER(info);<br></div><div dir="ltr"><br></div><div dir="ltr"> GstBuffer* bufferOut = gst_buffer_copy(buffer);<br></div><div dir="ltr"> if (bufferOut == NULL) {<br></div><div dir="ltr"> return GST_PAD_PROBE_OK;<br></div><div dir="ltr"> }<br></div><div dir="ltr"> GST_PAD_PROBE_INFO_DATA(info) = bufferOut;<br></div><div dir="ltr"> gst_buffer_unref(buffer);<br></div><div dir="ltr"><br></div><div dir="ltr"> guint64 framesCountFromOffsets = 0;<br></div><div dir="ltr"> if(GST_BUFFER_OFFSET_IS_VALID(bufferOut)) {<br></div><div dir="ltr"> guint64 offset = GST_BUFFER_OFFSET(bufferOut);<br></div><div dir="ltr"><br></div><div dir="ltr"> if(GST_BUFFER_OFFSET_END_IS_VALID(bufferOut)) {<br></div><div dir="ltr"> guint64 offsetEnd = GST_BUFFER_OFFSET_END(bufferOut);<br></div><div dir="ltr"> framesCountFromOffsets = offsetEnd - offset;<br></div><div dir="ltr"> }<br></div><div dir="ltr"> }<br></div><div dir="ltr"><br></div><div dir="ltr"> GstMapInfo mapInfoOut;<br></div><div dir="ltr"> if (gst_buffer_map (bufferOut, &mapInfoOut, GST_MAP_WRITE)) {<br></div><div dir="ltr"><br></div><div dir="ltr"> // Check that we are use correct buffer parameters<br></div><div dir="ltr"> printf("Data size = %d byte(s), frames count = %" G_GUINT64_FORMAT "\n",<br></div><div dir="ltr"> mapInfoOut.size,<br></div><div dir="ltr"> framesCountFromOffsets);<br></div><div dir="ltr"><br></div><div dir="ltr"> auto audioBufferPtr = reinterpret_cast<int16_t*>(mapInfoOut.data);<br></div><div dir="ltr"> generateSin(storage, audioBufferPtr, 250, 48000, 1, mapInfoOut.size / 2);<br></div><div dir="ltr"><br></div><div dir="ltr"> gst_buffer_unmap (bufferOut, &mapInfoOut);<br></div><div dir="ltr"> } else {<br></div><div dir="ltr"> g_print("Unable to write to the output buffer!\n");<br></div><div dir="ltr"> }<br></div><div dir="ltr"><br></div><div dir="ltr"> return GST_PAD_PROBE_OK;<br></div><div dir="ltr">}<br></div><div dir="ltr"><br></div><div dir="ltr">int pipelineCreate(Storage* storage,<br></div><div dir="ltr"> std::string const& outputHost,<br></div><div dir="ltr"> uint16_t outputPort,<br></div><div dir="ltr"> int argc,<br></div><div dir="ltr"> char* argv[]) {<br></div><div dir="ltr"><br></div><div dir="ltr"> gst_init (&argc, &argv);<br></div><div dir="ltr"><br></div><div dir="ltr"> storage->loop = g_main_loop_new(NULL, FALSE);<br></div><div dir="ltr"><br></div><div dir="ltr"> storage->pipeline = gst_pipeline_new("pipeline_test");<br></div><div dir="ltr"><br></div><div dir="ltr"> // Watch for messages on the pipeline's bus,<br></div><div dir="ltr"> // Note: it will work like this only when a GLib main loop is running.<br></div><div dir="ltr"> storage->bus = gst_pipeline_get_bus(GST_PIPELINE (storage->pipeline));<br></div><div dir="ltr"> storage->idWatch = gst_bus_add_watch(storage->bus, callbackBus,<br></div><div dir="ltr">storage->loop);<br></div><div dir="ltr"><br></div><div dir="ltr"> storage->src1 = gst_element_factory_make("audiotestsrc", "audiotestsrc1");<br></div><div dir="ltr"> storage->convert1 = gst_element_factory_make ("audioconvert",<br></div><div dir="ltr">"audioconvert1");<br></div><div dir="ltr"> storage->resample1 = gst_element_factory_make ("audioresample",<br></div><div dir="ltr">"audioresample1");<br></div><div dir="ltr"><br></div><div dir="ltr"> storage->capsfilter1 = gst_element_factory_make("capsfilter", "capsfilter1");<br></div><div dir="ltr"> GstCaps* caps = gst_caps_new_simple(<br></div><div dir="ltr"> "audio/x-raw",<br></div><div dir="ltr"> "format", G_TYPE_STRING, "S16LE",<br></div><div dir="ltr"> "rate", G_TYPE_INT, 48000,<br></div><div dir="ltr"> NULL);<br></div><div dir="ltr"> g_object_set(storage->capsfilter1, "caps", caps, NULL);<br></div><div dir="ltr"> gst_caps_unref(caps);<br></div><div dir="ltr"><br></div><div dir="ltr"> auto padSrcOfCapsFilter1 =<br></div><div dir="ltr">gst_element_get_static_pad(storage->capsfilter1, "src");<br></div><div dir="ltr"> if(padSrcOfCapsFilter1 == nullptr) {<br></div><div dir="ltr"> g_print("Failed to get an 'src' pad of the capsfilter1 element!\n");<br></div><div dir="ltr"> return -1;<br></div><div dir="ltr"> }<br></div><div dir="ltr"> storage->idProbe = gst_pad_add_probe(<br></div><div dir="ltr"> padSrcOfCapsFilter1,<br></div><div dir="ltr"> GST_PAD_PROBE_TYPE_BUFFER,<br></div><div dir="ltr"> static_cast<GstPadProbeCallback>(probe),<br></div><div dir="ltr"> static_cast<gpointer>(storage),<br></div><div dir="ltr"> NULL);<br></div><div dir="ltr"> gst_object_unref(padSrcOfCapsFilter1);<br></div><div dir="ltr"><br></div><div dir="ltr"> storage->opusenc1 = gst_element_factory_make("opusenc", "opusenc1");<br></div><div dir="ltr"><br></div><div dir="ltr"> storage->rtpopuspay1 = gst_element_factory_make("rtpopuspay", "rtpopuspay1");<br></div><div dir="ltr"> g_object_set(storage->rtpopuspay1,<br></div><div dir="ltr"> "pt", 96,<br></div><div dir="ltr"> NULL);<br></div><div dir="ltr"><br></div><div dir="ltr"> storage->udpsink1 = gst_element_factory_make("udpsink", "udpsink1");<br></div><div dir="ltr"> std::string addr = outputHost + ":" + std::to_string(outputPort);<br></div><div dir="ltr"> g_object_set(storage->udpsink1,<br></div><div dir="ltr"> "clients", addr.c_str(),<br></div><div dir="ltr"> "async", false,<br></div><div dir="ltr"> NULL);<br></div><div dir="ltr"><br></div><div dir="ltr"> gst_bin_add_many(GST_BIN(storage->pipeline),<br></div><div dir="ltr"> storage->src1,<br></div><div dir="ltr"> storage->convert1,<br></div><div dir="ltr"> storage->resample1,<br></div><div dir="ltr"> storage->capsfilter1,<br></div><div dir="ltr"> storage->opusenc1,<br></div><div dir="ltr"> storage->rtpopuspay1,<br></div><div dir="ltr"> storage->udpsink1,<br></div><div dir="ltr"> NULL);<br></div><div dir="ltr"><br></div><div dir="ltr"> // Link everything together<br></div><div dir="ltr"> if (!gst_element_link_many(<br></div><div dir="ltr"> storage->src1,<br></div><div dir="ltr"> storage->convert1,<br></div><div dir="ltr"> storage->resample1,<br></div><div dir="ltr"> storage->capsfilter1,<br></div><div dir="ltr"> storage->opusenc1,<br></div><div dir="ltr"> storage->rtpopuspay1,<br></div><div dir="ltr"> storage->udpsink1,<br></div><div dir="ltr"> NULL)) {<br></div><div dir="ltr"><br></div><div dir="ltr"> g_print("Failed to link one or more elements!\n");<br></div><div dir="ltr"> return -1;<br></div><div dir="ltr"> }<br></div><div dir="ltr"><br></div><div dir="ltr"> return 0;<br></div><div dir="ltr">}<br></div><div dir="ltr"><br></div><div dir="ltr">int pipelinePlay(Storage& storage) {<br></div><div dir="ltr"> GstStateChangeReturn ret = gst_element_set_state(storage.pipeline,<br></div><div dir="ltr">GST_STATE_PLAYING);<br></div><div dir="ltr"> if (ret == GST_STATE_CHANGE_FAILURE) {<br></div><div dir="ltr"> g_print("Failed to start up pipeline!\n");<br></div><div dir="ltr"><br></div><div dir="ltr"> // Check if there is an error message with details on the bus<br></div><div dir="ltr"> GstMessage* msg = gst_bus_poll(storage.bus, GST_MESSAGE_ERROR, 0);<br></div><div dir="ltr"> if (msg) {<br></div><div dir="ltr"> GError* err = NULL;<br></div><div dir="ltr"><br></div><div dir="ltr"> gst_message_parse_error(msg, &err, NULL);<br></div><div dir="ltr"> g_print("ERROR: %s\n", err->message);<br></div><div dir="ltr"> g_error_free(err);<br></div><div dir="ltr"> gst_message_unref(msg);<br></div><div dir="ltr"> }<br></div><div dir="ltr"> return -1;<br></div><div dir="ltr"> }<br></div><div dir="ltr"><br></div><div dir="ltr"> g_print("Playing...\n");<br></div><div dir="ltr"><br></div><div dir="ltr"> g_main_loop_run(storage.loop);<br></div><div dir="ltr"><br></div><div dir="ltr"> return 0;<br></div><div dir="ltr">}<br></div><div dir="ltr"><br></div><div dir="ltr">int pipelineDestroy(Storage& storage) {<br></div><div dir="ltr"> // Cleanup all<br></div><div dir="ltr"> gst_element_set_state(storage.pipeline, GST_STATE_NULL);<br></div><div dir="ltr"> gst_object_unref(storage.bus);<br></div><div dir="ltr"> gst_object_unref(storage.pipeline);<br></div><div dir="ltr"> g_source_remove(storage.idWatch);<br></div><div dir="ltr"><br></div><div dir="ltr"> g_main_loop_unref(storage.loop);<br></div><div dir="ltr"><br></div><div dir="ltr"> return 0;<br></div><div dir="ltr">}<br></div><div dir="ltr"><br></div><div dir="ltr">int main(int argc, char* argv[]) {<br></div><div dir="ltr"> Storage storage;<br></div><div dir="ltr"> storage.pos = 0;<br></div><div dir="ltr"><br></div><div dir="ltr"> std::string outputHost = "host.docker.internal";<br></div><div dir="ltr"> uint16_t outputPort = 50111;<br></div><div dir="ltr"><br></div><div dir="ltr"> int res = pipelineCreate(&storage, outputHost, outputPort, argc, argv);<br></div><div dir="ltr"> if(res != 0) {<br></div><div dir="ltr"> return res;<br></div><div dir="ltr"> }<br></div><div dir="ltr"><br></div><div dir="ltr"> res = pipelinePlay(storage);<br></div><div dir="ltr"> if(res != 0) {<br></div><div dir="ltr"> return res;<br></div><div dir="ltr"> }<br></div><div dir="ltr"><br></div><div dir="ltr"> res = pipelineDestroy(storage);<br></div><div dir="ltr"> if(res != 0) {<br></div><div dir="ltr"> return res;<br></div><div dir="ltr"> }<br></div><div dir="ltr"><br></div><div dir="ltr"> return res;<br></div><div dir="ltr">}<br></div></div>
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