Function CreateSilenceBuf

libhb/sync.c:290–347

}

static hb_buffer_t * CreateSilenceBuf( sync_stream_t * stream,
                                       int64_t dur, int64_t pts )
{
    double             frame_dur, next_pts, duration;
    int                size;
    hb_buffer_list_t   list;
    hb_buffer_t      * buf;

    if (stream->audio.audio->config.out.codec & HB_ACODEC_PASS_FLAG)
    {
        return NULL;
    }
    duration = dur;
    // Although frame size isn't technically important any more, we
    // keep audio buffer durations <= input audio buffer durations.
    frame_dur = (90000. * stream->audio.audio->config.in.samples_per_frame) /
                          stream->audio.audio->config.in.samplerate;
    // Audio mixdown occurs in decoders before sync.
    // So number of channels here is output channel count.
    // But audio samplerate conversion happens in later here in sync.c
    // FilterAudioFrame, so samples_per_frame is still the input sample count.
    size = sizeof(float) * stream->audio.audio->config.in.samples_per_frame *
                           hb_mixdown_get_discrete_channel_count(
                                    stream->audio.audio->config.out.mixdown);

    hb_buffer_list_clear(&list);
    next_pts = pts;
    while (duration >= frame_dur)
    {
        buf = hb_buffer_init(size);
        memset(buf->data, 0, buf->size);
        buf->s.start     = next_pts;
        next_pts        += frame_dur;
        buf->s.stop      = next_pts;
        buf->s.duration  = frame_dur;
        duration        -= frame_dur;
        hb_buffer_list_append(&list, buf);
    }
    if (duration > 0)
    {
        // Make certain size is even multiple of sample size * num channels
        size = (int)(duration * stream->audio.audio->config.in.samplerate /
                     90000) * sizeof(float) *
               hb_mixdown_get_discrete_channel_count(
                                    stream->audio.audio->config.out.mixdown);
        if (size > 0)
        {
            buf = hb_buffer_init(size);
            memset(buf->data, 0, buf->size);
            buf->s.start     = next_pts;
            next_pts        += duration;
            buf->s.stop      = next_pts;
            buf->s.duration  = duration;
            hb_buffer_list_append(&list, buf);
        }
    }
    return hb_buffer_list_clear(&list);
}