Convert Flac to TrueHD

[TBsq]

Hi, I want to convert a Flac audio track from a video to TrueHD. When I do this with Xmedia recode, it encodes it in "standard" DTS. Is there another way?

[Selur]

Are you sure Xmedia recoder can convert to TrueHD?
I thought the only tools capable of encoding TrueHD were those of Dolby itself.
So my guess is that you will have to invest quite a bit of money to get a TrueHD encoder,...

[sneaker]

ffmpeg has an (experimental) TrueHD encoder. (Getting AC3+TrueHD is a different problem, though.)

[TBsq]

Well I managed to make this conversion with Xmedia Recode, it was just in the format selection. So now I'm asking if is this real TrueHD?

[El Heggunte]

Well I managed to make this conversion with Xmedia Recode, it was just in the format selection. So now I'm asking if is this real TrueHD?

Use MediaInfo, or read what a professional BD authoring software says about it.

Also, keep in mind that ffmpeg's MLP/TrueHD encoder compresses so poorly that the result has almost the same size as uncompressed PCM.

[Selur]

@ElHeggunte: Is it really ffmpegs TrueHD encoder or is it TrueHD in general?

[sneaker]

I cannot confirm this either way after a few tests. For one random Hollywood movie with 5.1 ffmpeg TrueHD encoder achieved 68% bitrate saving (without AC3 core). It's content-dependent, though, with the lowest saving being closer to 25%.

[El Heggunte]

@ElHeggunte: Is it really ffmpegs TrueHD encoder or is it TrueHD in general?

I have just compared an ancient version of ffmpeg (4.1.4) with a fresh one (git-2020-04-26-1128aa8). In general this latter compresses somewhat-better than the old one, but it still doesn't have the same efficiency of the official encoders from Meridian/Dolby.

[Selur]

Thanks, good to know. btw. is there a freeware tool which can combine an ac3 and truehd stream into a ac3&truehd combi stream?
ffmpeg, tsMuxeR, eac3to (and probably mkvtoolnix) can be used to split the combi stream, but how to recombine it?

Cu Selur

[sneaker]

Haven't seen any, but eac3to can encode a (new) AC3 core to an existing core-less TrueHD file.