This is a quick test, if the YouTube Cloud Transcoder supports MXF-Contribution Quality for high quality uploads as it is used within ARD and ZDF. For a broadcaster it can be desirable to upload their productions in high quality to cloud-based video-portals like YouTube without any further recompression to maintain quality and save processing costs. To test this with the current YouTube-Transcoding Platform, IRT uploaded Testclips, which follow the basic requirements for the contribution of HD-Video within ARD/ZDF, as described in the so called “TPRF-HD” specification.
As it turns out, YouTube can handle both i/25 and p/50 Video provided in x264 high422 yuv422p intra at high bitrates up to 112 MBps very well but selects only the first Audio-Track, which is Mono in the Channel Layout, mandated in TPRF-HD auf ARD and ZDF, while it discards the other 7 Mono-tracks, which typically may contain Stereo-R + 5.1 Mono Tracks.
IRT test stream uploaded as MXF contribution quality TPRF-HD in the format 1920x1080i25 7bar 8ch x264 high422 yuv422p intra bit112M max112M buf112M using 8 mono audio layout channel.
IRT test stream uploaded as MXF contribution quality TPRF-HD in the format 1280x720p50 8bar 8ch x264 high422 yuv422p intra bit112M max112M buf112M using 8 mono audio layout channel.
As a workaround, the 2+6 Audio-Tracks could be re-mapped using ffmpeg without any re-encoding:
ffmpeg -i INPUT -filter_complex "[0:1][0:2]amerge" OUTPUT