container - compulsory; name of container; possible values: asf (WMV), mpeg (MPEG2PS), mpegts (MPEG2TS), mp4 (MPEG4, MOV), mpegvideo (MPEG1), matroska (MKV), avi, flv, wtv, ogg, 3gp
vCodec - optional; name of video codec of the original file or omit to transcode any video codec in the container; possible values: mpeg2video, mpeg1video, wmv2, mpeg4, msmpeg4, h264, vc1, mjpeg, flv, vp6, theora, dvvideo
aCodec - optional; name of audio codec of the original file or omit to transcode any audio codec in the container; possible values: aac, ac3, mp3, mp2, lpcm, wmav2, wmapro, dca (DTS), flac, vorbis, truehd, amrnb
profile - optional; H264 profile (in a case of H264 video stream); possible values: baseline, main, extended, high, high_422, high_444
levelGreaterThan - optional; H264 level (in a case of H264 video stream, in combination with profile attribute); possible values: level number, e.g. 4, 4.1, 5, etc.