Streaming Ogg Opus file

This example shows how to stream an Ogg Opus file to a voice channel. This example requires some additional dependencies, namely libogg and opusfile.

#include <dpp/dpp.h>
#include <iomanip>
#include <sstream>
 
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ogg/ogg.h>
#include <opus/opusfile.h>
 
int main(int argc, char const *argv[])
{
    /* Load an ogg opus file into memory.
     * The bot expects opus packets to be 2 channel stereo, 48000Hz.
     * 
     * You may use ffmpeg to encode songs to ogg opus:
     * ffmpeg -i /path/to/song -c:a libopus -ar 48000 -ac 2 -vn -b:a 96K /path/to/opus.ogg 
     */
 
    dpp::cluster bot("token");
 
    bot.on_log(dpp::utility::cout_logger());
 
    /* The event is fired when someone issues your commands */
    bot.on_slashcommand([&bot](const dpp::slashcommand_t& event) {
 
        /* Check which command they ran */
        if (event.command.get_command_name() == "join") {
 
            /* Get the guild */
            dpp::guild* g = dpp::find_guild(event.command.guild_id);
 
            /* Attempt to connect to a voice channel, returns false if we fail to connect. */
            if (!g->connect_member_voice(event.command.get_issuing_user().id)) {
                event.reply("You don't seem to be in a voice channel!");
                return;
            }
            
            /* Tell the user we joined their channel. */
            event.reply("Joined your channel!");
        } else if (event.command.get_command_name() == "play") {
 
            /* Get the voice channel the bot is in, in this current guild. */
            dpp::voiceconn* v = event.from->get_voice(event.channel.guild_id);
 
            /* If the voice channel was invalid, or there is an issue with it, then tell the user. */
            if (!v || !v->voiceclient || !v->voiceclient->is_ready()) {
                event.reply("There was an issue with getting the voice channel. Make sure I'm in a voice channel!");
                return;
            }
 
            ogg_sync_state oy; 
            ogg_stream_state os;
            ogg_page og;
            ogg_packet op;
            OpusHead header;
            char *buffer;
 
            FILE *fd;
 
            fd = fopen("/path/to/opus.ogg", "rb");
 
            fseek(fd, 0L, SEEK_END);
            size_t sz = ftell(fd);
            rewind(fd);
 
            ogg_sync_init(&oy);
 
            int eos = 0;
            int i;
 
            buffer = ogg_sync_buffer(&oy, sz);
            fread(buffer, 1, sz, fd);
 
            ogg_sync_wrote(&oy, sz);
 
            if (ogg_sync_pageout(&oy, &og) != 1) {
                fprintf(stderr,"Does not appear to be ogg stream.\n");
                exit(1);
            }
 
            ogg_stream_init(&os, ogg_page_serialno(&og));
 
            if (ogg_stream_pagein(&os,&og) < 0) {
                fprintf(stderr,"Error reading initial page of ogg stream.\n");
                exit(1);
            }
 
            if (ogg_stream_packetout(&os,&op) != 1) {
                fprintf(stderr,"Error reading header packet of ogg stream.\n");
                exit(1);
            }
 
            /* We must ensure that the ogg stream actually contains opus data */
            if (!(op.bytes > 8 && !memcmp("OpusHead", op.packet, 8))) {
                fprintf(stderr,"Not an ogg opus stream.\n");
                exit(1);
            }
 
            /* Parse the header to get stream info */
            int err = opus_head_parse(&header, op.packet, op.bytes);
            if (err) {
                fprintf(stderr,"Not a ogg opus stream\n");
                exit(1);
            }
 
            /* Now we ensure the encoding is correct for Discord */
            if (header.channel_count != 2 && header.input_sample_rate != 48000) {
                fprintf(stderr,"Wrong encoding for Discord, must be 48000Hz sample rate with 2 channels.\n");
                exit(1);
            }
 
            /* Now loop though all the pages and send the packets to the vc */
            while (ogg_sync_pageout(&oy, &og) == 1) {
                ogg_stream_init(&os, ogg_page_serialno(&og));
 
                if(ogg_stream_pagein(&os,&og)<0) {
                    fprintf(stderr,"Error reading page of Ogg bitstream data.\n");
                    exit(1);
                }
 
                while (ogg_stream_packetout(&os,&op) != 0) {
 
                    /* Read remaining headers */
                    if (op.bytes > 8 && !memcmp("OpusHead", op.packet, 8)) {
                        int err = opus_head_parse(&header, op.packet, op.bytes);
                        if (err) {
                            fprintf(stderr,"Not a ogg opus stream\n");
                            exit(1);
                        }
 
                        if (header.channel_count != 2 && header.input_sample_rate != 48000) {
                            fprintf(stderr,"Wrong encoding for Discord, must be 48000Hz sample rate with 2 channels.\n");
                            exit(1);
                        }
 
                        continue;
                    }
 
                    /* Skip the opus tags */
                    if (op.bytes > 8 && !memcmp("OpusTags", op.packet, 8))
                        continue; 
 
                    /* Send the audio */
                    int samples = opus_packet_get_samples_per_frame(op.packet, 48000);
 
                    v->voiceclient->send_audio_opus(op.packet, op.bytes, samples / 48);
                }
            }
 
            /* Cleanup */
            ogg_stream_clear(&os);
            ogg_sync_clear(&oy);
 
            event.reply("Finished playing the audio file!");
        }
    });
 
    bot.on_ready([&bot](const dpp::ready_t & event) {
        if (dpp::run_once<struct register_bot_commands>()) {
 
            /* Create a new command. */
            dpp::slashcommand joincommand("join", "Joins your voice channel.", bot.me.id);
 
            dpp::slashcommand playcommand("play", "Plays an ogg file.", bot.me.id);
 
            bot.global_bulk_command_create({joincommand, playcommand});
        }
    });
    
    /* Start bot */
    bot.start(dpp::st_wait);
 
    return 0;
}

You can compile this example using the following command

c++ /path/to/source.cc -ldpp -lopus -lopusfile -logg -I/usr/include/opus

Using liboggz

You can use liboggz to stream an Ogg Opus file to discord voice channel. liboggz provides higher level abstraction and useful APIs. Some features liboggz provides include: seeking and timestamp interpretation. Read more on the documentation.

#include <dpp/dpp.h>
#include <iomanip>
#include <sstream>
 
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <oggz/oggz.h>
 
int main() {
    /* Load an ogg opus file into memory.
     * The bot expects opus packets to be 2 channel stereo, 48000Hz.
     * 
     * You may use ffmpeg to encode songs to ogg opus:
     * ffmpeg -i /path/to/song -c:a libopus -ar 48000 -ac 2 -vn -b:a 96K /path/to/opus.ogg 
     */
 
    /* Setup the bot */
    dpp::cluster bot("token");
 
    bot.on_log(dpp::utility::cout_logger());
 
    /* The event is fired when someone issues your commands */
    bot.on_slashcommand([&bot](const dpp::slashcommand_t& event) {
 
        /* Check which command they ran */
        if (event.command.get_command_name() == "join") {
            /* Get the guild */
            dpp::guild* g = dpp::find_guild(event.command.guild_id);
 
            /* Attempt to connect to a voice channel, returns false if we fail to connect. */
            if (!g->connect_member_voice(event.command.get_issuing_user().id)) {
                event.reply("You don't seem to be in a voice channel!");
                return;
            }
            
            /* Tell the user we joined their channel. */
            event.reply("Joined your channel!");
        } else if (event.command.get_command_name() == "play") {
            /* Get the voice channel the bot is in, in this current guild. */
            dpp::voiceconn* v = event.from->get_voice(event.command.guild_id);
 
            /* If the voice channel was invalid, or there is an issue with it, then tell the user. */
            if (!v || !v->voiceclient || !v->voiceclient->is_ready()) {
                event.reply("There was an issue with getting the voice channel. Make sure I'm in a voice channel!");
                return;
            }
 
            // load the audio file with oggz
            OGGZ *track_og = oggz_open("/path/to/opus.ogg", OGGZ_READ);
 
            /* If there was an issue reading the file, tell the user and stop */
            if (!track_og) {
                fprintf(stderr, "Error opening file\n");
                event.reply("There was an issue opening the file!");
                return;
            }
 
            // set read callback, this callback will be called on packets with the serialno,
            // -1 means every packet will be handled with this callback
            oggz_set_read_callback(
                track_og, -1,
                [](OGGZ *oggz, oggz_packet *packet, long serialno,
                    void *user_data) {
                    dpp::voiceconn *voiceconn = (dpp::voiceconn *)user_data;
 
                    // send the audio
                    voiceconn->voiceclient->send_audio_opus(packet->op.packet,
                            packet->op.bytes);
 
                    // make sure to always return 0 here, read more on oggz documentation
                    return 0;
                },
                // this will be the value of void *user_data
                (void *)v
            );
 
            // read loop
            while (v && v->voiceclient && !v->voiceclient->terminating) {
                // you can tweak this to whatever. Here I use BUFSIZ, defined in
                // stdio.h as 8192
                static const constexpr long CHUNK_READ = BUFSIZ * 2;
 
                const long read_bytes = oggz_read(track_og, CHUNK_READ);
 
                // break on eof
                if (!read_bytes) {
                    break;
                }
            }
 
            // don't forget to free the memory
            oggz_close(track_og);
 
            event.reply("Finished playing the audio file!");
        }
    });
 
    bot.on_ready([&bot](const dpp::ready_t & event) {
        if (dpp::run_once<struct register_bot_commands>()) {
            /* Create a new command. */
            dpp::slashcommand joincommand("join", "Joins your voice channel.", bot.me.id);
            dpp::slashcommand playcommand("play", "Plays an ogg file.", bot.me.id);
 
            bot.global_bulk_command_create({ joincommand, playcommand });
        }
    });
    
    /* Start bot */
    bot.start(dpp::st_wait);
    
    return 0;
}

You can compile this example using the following command:

c++ /path/to/source.cc -ldpp -loggz