光学录音 meaning in English

optic sound recording
optical recording
optical sound recording
opticsound recording
photographic recording
photographic sound

Film 16 mm ; photographic sound record ; track position and slit image
16mm胶片.光学录音.声带位置和隙缝影象
Film 16 mm ; optical sound heads , requirements and general data for measuring
16mm胶片.光学录音头.测量要求和一般数据
Cinematography - photographic sound test films , 35 mm and 16 mm - specifications
电影摄影术. 35mm和16mm光学录音检验片.规范
Film 8 mm ; saturation level of optical sound records on film 8s ; definition , measurement
8mm胶片. 8s胶片光学录音的饱和度.定义测量