Re: curious difference between DTS and DSD version of same multichannel mix
Reply #9 – 2023-05-16 20:32:08
I suspect, but don't know for sure, that the old analog multitracks are digitized to PCM , not DSD. Likely.I extremely strongly suspect that multichannel mixing and production and mastering are done in the PCM realm It is certainly the case because digital mixing requires more than 1 bit, just a simple math 1+1=2. With 1 bit the bits can only be flipped. It does not make any sense to do all the mixing and effect processing using analog equipment then re-digitize to DSD again. Agreed but you might be surprised. It is definitely not unheard of in the mixing/mastering suite for a signal to go through an analog process again after being digitized (and then being redigitized for the final product) The final step is either release as lossless PCM (DVD-A or BluRay), or PCM encoded to DTS / AC3 (DVD-V), or PCM converted to DSD (SACD), depending on release format. So let's assume the SACD version of this track already underwent a PCM master -->DSD conversion. And the DTS version is a lossy encode of the PCM master. That means the clipping* seen in the DTS version was on the PCM master... or can encoding to DTS 96/24 introduce it? I am not familiar with the DTS lossy codec, but in general, transform-based lossy codecs work in a way like this:https://izotope-rx.livejournal.com/5760.html So basically, if you convert these lossy formats to fixed point PCM instead of floating point, clipping could be introduced due to the fact that fixed point formats cannot contain any >0dBFS sample value. Does the conversion software you use capable of floating point decoding? I used ffmpeg to decode the raw DTS file. Simply this: ffmpeg -i inputfile.dts outputfile.wav If the input dts file is dts 96/24, the decoded output file is 96/24 PCM. If it's 'plain' (aka core) DTS, the decoded output is 48/24 PCM version info:ffmpeg version N-93774-gfec4212d8e Copyright (c) 2000-2019 the FFmpeg developers built with gcc 8.3.1 (GCC) 20190414 configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-amf --enable-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt libavutil 56. 26.101 / 56. 26.101 libavcodec 58. 52.101 / 58. 52.101 libavformat 58. 27.103 / 58. 27.103 libavdevice 58. 7.100 / 58. 7.100 libavfilter 7. 50.100 / 7. 50.100 libswscale 5. 4.100 / 5. 4.100 libswresample 3. 4.100 / 3. 4.100 libpostproc 55. 4.100 / 55. 4.100 Foobar2K, Audiomuxer, and DVD Audio Extractor also do DTS decoding, but I didn't use them and I'm not sure if they all decode DTS 96/24 , and how.