mp4_aac+_320_240_v104_10_a16_44_m.sdp
mp4_aac+_320_240_v256_20_a24_44_s.sdp
mp4_aac+_320_240_v384_30_a48_48_s.sdp
mp4_aac+_vbr_320_240_v196_15_a24_32_m.sdp
mp4_aac+_vbr_320_240_v308_25_a32_44_m.sdp