Tutorial MCH Music, SACD options and ISO/DSF/DFF file formats

Discussion in 'HDD Media player(RTD 1296)' started by Nice Monkey, Jul 9, 2020.

  1. Nice Monkey

    Nice Monkey Well-Known Member Beta test group

    Introduction to the SACD disc basics and options
    SACD discs are commonly Hybrid with a normal CD player first layer for backward compatibility playback on ordinary CD-players and a second SACD layer (DVD type data layer) for SACD playback in DSD64 1-bit sample format on specifically SACD capable players.
    There are a few DSD128 and even fewer DSD256 original studio SACD's with higher sampler rates.

    The SACD layer has mostly 2CH (=Stereo) tracks but may optionally have MCH (=Multi Channel 5.1) tracks additionally. So a HW based SACD player lets users then select CD, 2CH or MCH playback for those albums having all three on them. The exact content/playback capabilities are always displayed on the disc and labels accordingly. To make bigger contents fit on the SACD layer this may be compressed using DST (Direct Stream Transfer). MCH SACD albums always use DST compression to make them fit on the DVD layer. SACD's sales almost came to a hold with just a few small labels still producing them for a very specific audience.

    Truly enjoying MCH music and SACD playback!
    SACD was maybe developed and marketed too early in time by Philips/Sony. Producing DAC's that could handle the DSD format well did not really exist yet and very few people having a quality 5.1 audio setup to truly enjoy MCH. This caused a lot of debate if DSD was really superior to PCM (CD <=> SACD). Now 30 years later this all changed as not only the quality of the DAC's and AMP's improved but also the clock circuitry used with it made many improvements steps. The accuracy and phase jitter of the clock oscillators feeding a DAC was found to play a huge role in sound reproduction. For the excellent SACD format it seems that these innovations just came too late which is a real pity as the quality difference is a lot easier to perceive. With my setup all visitors can hear it doing A/B blind tests.

    It is my practical experience that you can only squeeze out maximum MCH 5.1 sound quality using a consistent choice of speakers (same brand and even model range). Using a mixed bag of speakers for front, center and back channels never gives satisfactory audio results. It may result very acceptable for movies (getting those effects) but definitely not for top quality music reproduction. I know it is a big temptation to use simpler/cheaper speakers for center and back channels, but frankly you should not do so when targeting for MCH 5.1 music listening too. Learned it myself the hard way changing my speaker setup in various steps.
    Really love the MCH sound on various SACD (DTS-CD/BD) music albums now. On some regular CD's the DSP provided up-scaling to DTS/THX 7.1 with my HT AMP produces pretty nice results too.

    There is a curious parallel between MCH music and 3D Video as both formats keep disappearing and making a come back with a newer technology. For music we first saw Quad LP, next MCH SACD, DTS-CD, DVD-Audio, BD Pure Audio. Now only BD Concerts with occasionally MCH DD/DTS audio tracks on them are actively produced by the big labels. Came across a curious collection of Quad LP recordings transferred by a studio to DTS-CD's which sound amazingly well this despite the age of the original recordings.

    ISO/DSF/DFF files
    Ripping an SACD results in an SACD ISO container with the DVD layer content only. The CD-layer is never part of it. Obviously that layer can be ripped using normal DAE (Digital Audio Extraction) tools if desired too. The SACD ISO contains all 2CH and/or MCH DSD tracks with or without DST compression as the final result. It is not possible to distinct the various options used without opening the container.

    - Individual tracks can next be extracted from the full SACD ISO in DSF or DFF file format. Both are maintaining the original DSD 1-bit sampling format of the ISO. DSF (Sony) does not facilitate DST compression but DFF (Philips) does optionally. Having a DSF track you can be sure it is not compressed with DST anymore and only DSF supports tagged meta data making it the most popular extraction format.
    - SACD ISO's with just 2CH tracks on them are mostly not DST compressed but when combined with MCH also those 2CH tracks are always compressed to reduce the total disc size. A MCH album would be 4x the size of an equivalent 2CH album without using DST compression!
    - MCH albums have also 2CH tracks on them but there are a few very rare exceptions known (mostly classical concerts it seems). 2CH and MCH tracks hence need to be extracted individually. You can't see if a DSF or DFF file is MCH or 2CH and neither if a DFF file uses DST compression or not. If all Stereo (2CH) tracks aren't very short but the album is still around 1 Gbyte (ISO or DFF's) then it probably is DST compressed.
    - It takes roughly 3x the total duration to extract a DST compressed SACD ISO to DSF or to DFF with DST decompression selected versus direct extraction to DFF with DST left untouched. MCH is 3x 2CH regarding size and it takes proportional resources to extract those tracks. So extracting a MCH DST track takes 9x the processing power compared to a 2CH uncompressed track! This is important to realize as it all needs to be done real time using media players in software which many can't cope with or not cope with well resulting in distorted playback if supported at all.
    - DST is indeed very effective in size reduction (album reduced with roughly a factor 2.5). But even using DST some long MCH albums may still not fit on a single DVD layer. These then use both DVD layers for just the SACD tracks skipping the Hybrid CD compatibility layer as the consequence. Not a very common format but have a few of those myself (resulting ISO > 4.7 GByte).

    Media player (restricted) SACD/DSD capabilities
    Most (Android) music player platforms and player APP's don't support DST at all or are not doing the decompression well real time. This is often not stated clearly as DST in fact is hardly ever mentioned at all anywhere and is e.g. never indicated on the SACD disc or labels. Some HW based players may NOT support MCH tracks for exactly that same reason without stating so explicitly.

    Music players claiming support for SACD/DSD will all at least be capable to playback DSF files and will mostly also play uncompressed DFF files. Many have problems with compressed DFF and only a very few can handle (compressed) ISO's correctly. Standardizing on DSF is therefore a popular method for many, this despite the far bigger size compared with compressed ISO/DFF. Personally I always only keep the original ISO's with just the converted MCH FLAC tracks added for the MCH SACD albums specifically as that is my only way to play those now (beyond playing the original physical discs).

    Media players unfortunately don't support native DSD output via HDMI and/or Analog output and will convert DSD streams to PCM streams real time when being played. Only HiFi media players with advanced onboard DAC's will output DSD directly when switched to Analog Output using such DSD capable DAC.

    Only a few media players like Zidoo can (or will try to) play MCH ISO's but in fact playing then the 2CH tracks. But also Zidoo Music Player has distortion problems playing MCH ISO's when converting these to 2CH PCM via HDMI specifically due to the need for DST decompression. Using X20 Pro and UHD2000 HiFi models there are no such performance problems anymore. When switching to DAC Analog output the need for DSD=>PCM conversion disappears which reduces the processor load enough to get into the safety zone.
    There are currently no Android based HiFi media players supporting MCH DAC's so that method restricts output to 2CH (Stereo) playback only.

    Also playing MCH FLAC one may run into CPU limitations as going above 88.2/96 kHz sample rates with 24-bit depth may already start to produce distortions.

    The new RTD1619 based media players are maybe capable to do MCH DSF => MCH PCM output as that total load is only marginally above MCH SACD/DSD ISO => 2CH PCM playback. MCH SACD/DSD ISO => MCH PCM most likely remains far out of reach. Uncompressed MCH DFF on the other hand should be possible as that is similar load to MCH DSF. Using appropriate drivers MCH DSD via HDMI could potentially work too?

    Corrections, comments and questions are as always very welcome.
     
    Last edited: Jul 10, 2020
  2. lexalalex

    lexalalex New Member

    new firmware for "Dune HD Pro 4K II" can decoding of multichannel SACD audio files which use DST compression (DFF and ISO) to multichannel PCM.

    "
    - New feature: Pro 4K II model: Added support for decoding of multichannel
    SACD audio files which use DST compression (DFF and ISO) to multichannel
    PCM. Now, such files can be played with multichannel PCM output to HDMI.
    A new setting "Setup / Playback / Parameters / Preferred SACD area" can
    be used to choose, for images, which contain simultenously multichannel
    and stereo variants, which variant to use (default is Multichannel).
    (NOTE: not supported on older Realtek models, because CPU power of older
    models is not enough for stable playback.)

    - Improvement: Realtek models: Added support for playback of very large
    (very long) audio files in various lossless formats (SACD DSF/DFF/ISO,
    FLAC, APE, WavPack) (for examples, 192/24 audio file longer than 70
    minutes could not be played before, because of internal 32-bit
    limitation).
    "
    https://dune-hd.com/firmware/pro4k2/
     
    gymnos likes this.
  3. gymnos

    gymnos Member

    What about Zidoo players?
     
  4. Reelyator

    Reelyator Active Member

    Dear Nice Monkey,
    thank you for this nice Tutorial!!

    I have several SACD-Iso´s on my NAS wich i tried to play through several Players on my X20:
    1) Zidoo Mucic Player
    2) Kodi 18.09 with the "SACD Iso Support Add-on"

    Both approaches were not very convincing.
    1) is a mess because the imoport constantly crashes. The imported files are hardly connected to the correct Albums and Artists and there is ZERO feedback from the Zidoo Support team if you ask what to to to allow the correct detection of Artists and Albums. As far as i rememnber MCH has never worked.
    2) works a bit better than 1) ~50% play correctly, the rest is just noise. The biggest bug (in the most recent version 1.0.4 of the Add-on is the fact that after installation BD- DVD- and UHD-Iso files are not detected anymore by the Kodi Video Library. MCH never worked as well. The detection of Artist, Album, Title... is a bit better than 1) but still far away from reliable. Album Names are displayed as Artists, Albums have no Artists at all, Compilation Albums (with several artists) are not imported at all....

    Summing up: The Zidoo Music Player (latest version) is useless for SACD Iso Playback. I hope the problems of the SACD Iso Support Add-on for Kodi will be worked on in the future. As the Add-on is already listed on the Matrix Repository i hope to see some updates in the near future.

    If anybody here knowns. how to modify the Media-Tags embedded in SACD-Iso´s then please let me know!
     
    gymnos likes this.
  5. Reelyator

    Reelyator Active Member

    Short Update: Under Matrix there is now a new/compeletely reworked Version of the SACD Iso Support Add-on in the Kodi Repo. Now under Audio Decoders instead of VFS.

    The good news:
    Believe it or not: The new Version (0.1.2 under Audio Decoders) now allows MULTICHANNEL Playback!!!

    The bad news:
    The Hardware of the x20 seems to be way too weak to handle Multichanel Playback with this Add-on:-( Only stuttering playback. I would be curious to hear, how the newer dedicated High End Players like the UHD3000/2000 perform with this Add-on in MCH-Playback....
     
  6. Reelyator

    Reelyator Active Member

    @Nice Monkey : You seem to be the biggest expert here when it comes to MCH Music. Have you found a way to play MCH from SACD Iso´s using Kodis SACD Iso Support Add-on? I have started a separate Thread, just for this Add-on but up to now unfortunately with ZERO feedback from any other Zidoo users....
    The Add-on works with Stereo Playback but unfortunately no stable Playback with MCH. At Least not on my x20 but i would be curious if anybody could make it work, maybe with another more performant device...

    Your Thoughts??
     
  7. Nice Monkey

    Nice Monkey Well-Known Member Beta test group

    There are 2 ways to play MCH SACD ISO: DSD MCH directly and via DSD MCH => PCM MCH.

    For the time being we can forget about DSD as no one has ever produced an Android driver working via HDMI. If it can be done? I just got the rumor that work on it is being done.

    The RTD1619 SOC is proven fast enough to do the second method as Dune made this feature a sales highlight for their latest models. Zidoo players on previous RTD SOC's had troubles playing the 2CH tracks via DSD =>PCM extracting these live from the ISO container (2CH+MCH). The latest generation at least does that now without problems. If they manage to do so also for the MCH tracks is wait and see. The efficiency of the own OS used by Dune seems to be better positioned here than Android 9? Playing MCH DSF should be at least achievable as the decompression is then already done. That last statement should be true for KODI too.

    I am not a KODI user and can't comment on that aspect in any way.

    So far my 2 cents.
     
    Last edited: Mar 8, 2021
  8. Reelyator

    Reelyator Active Member

    After posting the MCH Issue on Github i have a Feedback from one of the Team Kodi Members wich sounds a bit frustrating related to the Android OS in kombination with Kodi. Quote:

    "For bitperfect audio in general, you should use an OS that can open "direct connections" to the sound hardware, e.g. Windows + WASAPI or Linux with ALSA.
    On Android in general you rely on the "soundserver" which is Audiotrack. So whatever kodi can do is just "get it right" out of kodi, afterwards the OS does whatever it wants. The really only way around this (100%) is using a format that they can't touch with a sink that they can't touch. This is IEC passthrough. So you won't like this, but if you convert the SACD to e.g. truehd, dts-hd - Android can not break it as it's then kodi doing the IEC packing and outputting without Android touching it IF your AVR / whatever supports that kind of format and the Android box needs to as well (IEC format that is).
    For the other passthrough format (RAW), Android has the say in packing ... therefore breaks it again :)
    For PCM content that is not passed through, but decode to PCM and output with the "best capability" the device offers from kodi's POV. Afterwards the soundserver (audiotrack) takes over and does whatever it wants ...
    As a founded conclusion: If you want high quality pcm / flac / whatever audio in all cases Android is the wrong choice."

    I would be curious to hear What the Zidoo Developers have to say about this topic. Considering that the UHD3000/2000... are marketed as "Ultimate HiFi Flagship with multiple innovative underlying AV decoding technologies" They should have a position on this..... Or even a solution...

    Too Sad that nobody from Zidoo is ever participating in their own forum.
     
    gymnos likes this.
  9. Reelyator

    Reelyator Active Member

    If not Kodi, what Player would you suggest for Playback from SACD Iso´s? The Zidoo Music Player is imho not even capable to import a SACD Iso Database without crashing permanently....
     
  10. Nice Monkey

    Nice Monkey Well-Known Member Beta test group

    I am using MP6 for SACD and that in general works just fine for what is supported now. :)

    Oh problems with the database? I never have any problems with it as I simply don't use it (yet). The DB has a very different way of organizing music than my own preferences. I just use Media Center to find one of my albums (organized my own way) and play those straight from there. ;)
    I neither like HiFi media players doing a zillion things in the background and turn everything off where possible: No scans, no updates, no lyrics, no meta data lookups etc. On demand foreground quiries is something else.

    Zidoo modifies the Android Leanback kernel to get passed some of those very serious Android limitations and use their own audio drivers for HiFi music. For that part they get around limitations nicely but controlling all other Android peculiarities and processes must be a constant challenge for them. :eek:

    Running KODI on a Linux based OS is much easier and cleaner. There are KODI based (mostly very cheap) media players just doing that
     
    Last edited: Mar 9, 2021
  11. Reelyator

    Reelyator Active Member

    ....just checked the Article Description of the current High End Model Zidoo UHD3000 and realized that this only claims SACD Iso Support (Stereo). This indicates that Zidoo is well aware about the limitations with MCH Playback,

    Therfore i would conclude that we have no other option than wait and see if this can be adressed in the future....maybe on some TBA Models, UHD9000.... who knows?
     
    gymnos likes this.
  12. Reelyator

    Reelyator Active Member

    Hi Nice Monkey.
    i am just trying out the Foobar SACD Plugin on my MCH SACD Iso´s. Have you used this before? Is there any Setting/Workflow you can recomment for lossless conversion of MCH with the original bit depth and sampling rate?
     
    Last edited: Jul 5, 2021
  13. Nice Monkey

    Nice Monkey Well-Known Member Beta test group

    For conversions I use the excellent xrecode3 program (Windows).
    Worked fine for me to play SACD ISO MCH DSD => MCH PCM conversions. Use my OPPO for SACD now.

    This topic was integrated here:
    http://forum.zidoo.tv/index.php?thr...useful-stuff-for-hifi-players-playback.86336/
    This here won't be updated anymore.
     
    Last edited: Jul 6, 2021
  14. kam186

    kam186 Member

    Nice Monkey, For Z9S model, do you know why SACD ISO file stream by network with jerking sound. Direct USB no problem at all ? Any idea why ??
     
  15. Nice Monkey

    Nice Monkey Well-Known Member Beta test group

    That process is running on the limits of its CPU capabilities. Network probably takes even a bit more resources. Convert to DSF and you will know. That is also the bypass.
     
    kam186 likes this.
  16. I run a China Oppo M9205, and playback via HDMI is perfect for SACD Multichannel even over NSF. It does not work over SMB for some reason. The Oppo converts to PCM before sending the multichannel to my Arcam AVM 850 as the Arcam does not have support for direct DSD.
     
  17. steveoat87

    steveoat87 New Member

    Hi,

    I carefully read your primer. I have a z2000 pro that doesn't let me play multichannel dsf files. To your knowledge, is this limitation being addressed. Any other ideas on how you can play these files? I am outputting everything to a denon 4800h receiver.
     

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