Using libvlc to extract raw frames and audio from media via smem

vlcsms.c

//To compile:
//cc vlcsms.c -o vlcsms -lvlc
//This source is by Tim Sheerman-Chase and it is released as public domain.

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <unistd.h>
#include <inttypes.h>
#include <vlc/vlc.h>

int done = 0;
libvlc_media_player_t *media_player = NULL;
uint8_t *videoBuffer = 0;
uint8_t *audioBuffer = 0;
unsigned int videoBufferSize = 0;
unsigned int audioBufferSize = 0;

// Audio prerender callback
void cbAudioPrerender (void* p_audio_data, uint8_t** pp_pcm_buffer , unsigned int size)
{
    // TODO: Lock the mutex
    //printf("cbAudioPrerender %i\n",size);
    //printf("atest: %lld\n",(long long int)p_audio_data);
    if (size > audioBufferSize || !audioBuffer)
    {
        printf("Reallocate raw audio buffer\n");
        if(audioBuffer) free(audioBuffer);
        audioBuffer = (uint8_t *)malloc(size);
        audioBufferSize = size;
    }
    *pp_pcm_buffer = audioBuffer;
}

// Audio postrender callback
void cbAudioPostrender(void* p_audio_data, uint8_t* p_pcm_buffer, unsigned int channels, unsigned int rate, unsigned int nb_samples, unsigned int bits_per_sample, unsigned int size, int64_t pts )
{
    //printf("cbAudioPostrender %i\n", size);
    // TODO: explain how data should be handled
    // TODO: Unlock the mutex
}

void cbVideoPrerender(void *p_video_data, uint8_t **pp_pixel_buffer, int size) {

       // Locking
    //printf("cbVideoPrerender %i\n",size);
    //printf("vtest: %lld\n",(long long int)p_video_data);
    if (size > videoBufferSize || !videoBuffer)
    {
        printf("Reallocate raw video buffer\n");
        if(audioBuffer) free(videoBuffer);
        videoBuffer = (uint8_t *)malloc(size);
        videoBufferSize = size;
    }
    *pp_pixel_buffer = videoBuffer;
}

void cbVideoPostrender(void *p_video_data, uint8_t *p_pixel_buffer
      , int width, int height, int pixel_pitch, int size, int64_t pts) {
    //printf("cbVideoPostrender %i\n",size);
   // Unlocking

}

static void handleEvent(const libvlc_event_t* pEvt, void* pUserData)
{
    libvlc_time_t time;
    switch(pEvt->type)
    {
    case libvlc_MediaPlayerTimeChanged:
        time = libvlc_media_player_get_time(media_player);
        printf("MediaPlayerTimeChanged %lld ms\n", (long long)time);
        break;
    case libvlc_MediaPlayerEndReached:
        printf ("MediaPlayerEndReached\n");
        done = 1;
        break;
    default:
        printf("%s\n", libvlc_event_type_name(pEvt->type));
    }    
}

int main(int argc, char **argv)
{
        // VLC pointers
        libvlc_instance_t *vlcInstance;
        void *pUserData = 0;

        // VLC options
       char smem_options[1000];
       sprintf(smem_options
          , "#transcode{vcodec=I444,acodec=s16l}:smem{"
             "video-prerender-callback=%lld,"
             "video-postrender-callback=%lld,"
             "audio-prerender-callback=%lld,"
             "audio-postrender-callback=%lld,"
             "audio-data=%lld,"
             "video-data=%lld},"
          , (long long int)(intptr_t)(void*)&cbVideoPrerender
          , (long long int)(intptr_t)(void*)&cbVideoPostrender
          , (long long int)(intptr_t)(void*)&cbAudioPrerender
          , (long long int)(intptr_t)(void*)&cbAudioPostrender
          , (long long int)100 //This would normally be useful data, 100 is just test data
          , (long long int)200); //Test data

        const char * const vlc_args[] = {
              "-I", "dummy", // Don't use any interface
              "--ignore-config", // Don't use VLC's config
              "--extraintf=logger", // Log anything
              "--verbose=1", // Be verbose
              "--sout", smem_options // Stream to memory
               };

        // We launch VLC
        vlcInstance = libvlc_new(sizeof(vlc_args) / sizeof(vlc_args[0]), vlc_args);

        media_player = libvlc_media_player_new(vlcInstance);
        libvlc_event_manager_t* eventManager = libvlc_media_player_event_manager(media_player);
        libvlc_event_attach(eventManager, libvlc_MediaPlayerTimeChanged, handleEvent, pUserData);
        libvlc_event_attach(eventManager, libvlc_MediaPlayerEndReached, handleEvent, pUserData);
        libvlc_event_attach(eventManager, libvlc_MediaPlayerPositionChanged, handleEvent, pUserData);

        libvlc_media_t *media = libvlc_media_new_path(vlcInstance, "test.wav");
        libvlc_media_player_set_media(media_player, media);
        libvlc_media_player_play(media_player);
        
        while (!done)
        {
            sleep(1);         
            //libvlc_media_player_set_position(media_player, 0.);
        }
        libvlc_media_release(media);
        return 0;
}