- int64_t total_audio_frames = video_frames_to_audio_frames (_film->length().get(), _film->audio_stream()->sample_rate(), _film->frames_per_second());
- _samples_per_point = total_audio_frames / _num_points;
+ int64_t total_audio_frames = video_frames_to_audio_frames (_film->length().get(), _film->audio_stream()->sample_rate(), _film->source_frame_rate());
+ _samples_per_point = max (int64_t (1), total_audio_frames / _num_points);