Flagging 1080p25 as 1080i25 without re-encoding

[Dr. Cooper]

Hi everyone,

I'm trying to create a Blu-ray from a TV-show I recorded. There's also been an online-press-conference for that show which I'd like to include as a bonus-feature on the disc. However, the video from that download is 1080p at 25 FPS, which isn't supported in the Blu-ray specs.

These are the full video-details from MediaInfo:

Video
ID                                       : 1
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : High@L5
Format settings                          : CABAC / 4 Ref Frames
Format settings, CABAC                   : Yes
Format settings, Reference frames        : 4 frames
Codec ID                                 : V_MPEG4/ISO/AVC
Duration                                 : 59 min 25 s
Bit rate                                 : 4 497 kb/s
Width                                    : 1 920 pixels
Height                                   : 1 080 pixels
Display aspect ratio                     : 16:9
Frame rate mode                          : Constant
Frame rate                               : 25.000 FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Bits/(Pixel*Frame)                       : 0.087
Stream size                              : 1.87 GiB (99%)
Default                                  : Yes
Forced                                   : No

The video-level also needs to be changed to 4.0 or 4.1 to match Blu-ray-specs, but that can be easily done using tsMuxeR. The rest should be ok, except for the progressive/interlaced-thing.

I know that there's a setting when encoding the video with x264 which is called "fake-interlaced". It's used to make a progressive encode, but adding an interlaced-flag to the video, so it is Blu-ray-compatible. Is there any way to add such a flag to this video, or is the only way to get it Blu-ray-compliant a re-encode?

I already tried changing the header-information in the MKV of the original file and MediaInfo shows that file as interlaced afterwards, but unfortunately tsMuxeR still recognizes it as progressive and muxes it as 1080p again.

Any idea how I can solve that issue without re-encoding the video or is it impossible and an encode can't be avoided?

[spoRv]

You can always flag it as 24fps, so the video will not be re-encoded; problem is, you have to re-encode audio, though...

[Dr. Cooper]

The audio needs to be re-encoded either way (the source is AAC), but I'd prefer to keep it at 25 FPS since it has been produced that way.

[FreaQ]

I do not think this is possible without reencoding.
Also you do not want to convert it to 1080i25 but to 1080i50. This would be the proper way to do it.