I need to write function in C that changes sample rate of one audio channel (float linear array).

I have this now:

int resample_audio(float *audio_input, int input_sample_rate, int output_sample_rate, int input_num_of_samples, float *audio_output, int *result_num_of_samples) {
    SwrContext* swr_ctx = swr_alloc();
    if (!swr_ctx) {
        fprintf(stderr, "Could not allocate SwrContextn");
        return -1;
    }

    av_opt_set_int(swr_ctx, "in_channel_layout",  AV_CH_LAYOUT_MONO, 0);
    av_opt_set_int(swr_ctx, "out_channel_layout", AV_CH_LAYOUT_MONO, 0);
    av_opt_set_int(swr_ctx, "in_sample_rate",     input_sample_rate, 0);
    av_opt_set_int(swr_ctx, "out_sample_rate",    output_sample_rate, 0);
    av_opt_set_sample_fmt(swr_ctx, "in_sample_fmt",  AV_SAMPLE_FMT_FLT, 0);
    av_opt_set_sample_fmt(swr_ctx, "out_sample_fmt", AV_SAMPLE_FMT_FLT, 0);

    if (swr_init(swr_ctx) < 0) {
        fprintf(stderr, "Failed to initialize the resampling context: %sn", av_err2str(swr_init(swr_ctx)));
        swr_free(&swr_ctx);
        return -1;
    }

    uint8_t **resampled_data = NULL;
    int output_samples_count = av_rescale_rnd(swr_get_delay(swr_ctx, input_sample_rate) + input_num_of_samples, output_sample_rate, input_sample_rate, AV_ROUND_UP);
    if (av_samples_alloc_array_and_samples(&resampled_data, NULL, 1, output_samples_count, AV_SAMPLE_FMT_FLT, 0) < 0) {
        fprintf(stderr, "Could not allocate samplesn");
        swr_free(&swr_ctx);
        return -1;
    }
    
    const uint8_t *in_samples[1] = {(const uint8_t *)audio_input};

    int frame_count = swr_convert(swr_ctx, resampled_data, output_samples_count, in_samples, input_num_of_samples);
    if (frame_count < 0) {
        fprintf(stderr, "Error while resamplingn");
        av_freep(&resampled_data[0]);
        free(resampled_data);
        swr_free(&swr_ctx);
        return -1;
    }

    audio_output = (float *) malloc(sizeof(float) * frame_count);

    *result_num_of_samples = frame_count;

    // exception

    memcpy(audio_output, resampled_data[0], frame_count * sizeof(float));

    av_freep(&resampled_data[0]);
    free(resampled_data);
    swr_free(&swr_ctx);
    return SUCCESS;
}

Every audio that I try to re-sample gives error : Invalid argument in line with initializing SWR context (swr_init(swr_ctx) < 0). Please , help me fix that …