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USB Audio Recorder PRO (UAPP): 24- and 32-bit playback, ubiquitous USB audio support for Android

Discussion in 'Portable Source Gear' started by nztechfreak, Feb 5, 2014.
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  1. Davy Wentzler
    I sure hope that when we pass floating point values using AudioTrack, that you don't simply cast but scale? Otherwise the audio would be silent.
    buonassi likes this.
  2. superuser1
    Interesting discussion ....
    I am waiting for a conclusion!!
    buonassi likes this.
  3. Lurker0
    Even less than 24 bits! But we are speaking about bit perfect pass-through and not DAC or hearing possibilities. Bit perfect pass-through may be required to send encoded stream via S/PDIF or USB to a decoder, or even to internal DAC, if it can decode. It can be MQA, AC3, DTS, DSD in DoP... whatever and must come through bit perfect. Native DSD stream is usually sent as 32-bit samples. My tests for bit perfect playback exactly include DTS and DoP. You may check different apps on your devices and see yourself how many actually pass 16 (DTS) and 24 (DoP) bits tests. Well, yes, for HiBy DAPs 32-bit pass through is not needed, but, certainly, not because of Heisenberg :wink:
    Dannemand and buonassi like this.
  4. yorosello
    I had enabled the 'Enable USB Hardware button' , yet I still can't use my USB DAC's button to stop/ change track. Only volume was working. Also, the option to pause on unplug headphones were not working as well. Both says I need to restart the app, but after trying almost 10 times to restart & reconnect the DAP, nothing had happened too. Any way to solve this?
    Last edited: Oct 23, 2019
  5. Joe Bloggs Contributor
    Yes, of course, scale, I was paraphrasing from the Chinese engineering team

    All these applications are 16 or 24 bits. 32 bit bit perfect remains exactly as I had described it, a fool's errand. And again, even for them, you can use pcm_offload.

    Main problem you'd actually run into, is that the DAPs don't detect and decode DTS or DoP at that stage of the pipeline. So what you speak of is only useful for USB or coax output. But USB, that's what UAPP is for isn't it? And we're running our own certification for MQA with... MQA.
    Last edited: Oct 23, 2019
    buonassi likes this.
  6. scottm18
    Davy...any chance of dabbling with the dual screen feature of the LG V50 and G8x as an option? Could make for some interesting scenarios like full album art and navigation on one screen and music library scanning on the other while running UAPP. The latter phone is finally coming the the US in Nov WITH the dual screen and i may pick one up to replace my V40...
    Last edited: Oct 23, 2019
  7. buonassi
    I'm loving this technical discussion about the bitstream! This is the stuff I love learning about and what I believe to be a very important aspect of 'implementation'.

    Likes all around guys
    WitzyZed and superuser1 like this.
  8. Lurker0
    In particular :)
    Not only.

    Joe, you see, I truly believe that your team has made a great job to allow other apps to fully utilize your DAPs audio part! But, for software developers and end users, it means nothing.

    The problem is that the second peer is always involved: the software music player actually used. And here you can guarantee nothing! You can't ensure that Tidal or Spotify (or any other software player) actually passes even 16 bits into your advanced system bit perfect. You can't guarantee that Amazon Music HD would play 24/192 bit perfect. But that's exactly what the end user is concerned about: he buys a DAP, he buys some other hardware (headphones at least but also external DACs, amps etc), then he buys music and wants to be confident that each bit of music he paid for is not discarded.

    Audiophiles are concerned even about 32 bits (they mostly didn't study physics), or S/PDIF output (that you silently left alone :wink:). They are concerned even about a USB DAC connected to an Android device, despite it was advertised that Android has built-in support... just like you advertised DTA :p There is no a difference between those ads for end users here. They want to be confident!

    And here is UAPP and alike, the software music players that guarantee bit perfect playback from any source file supported on any device supported. And, like you can guarantee nothing regarding 3rd party music players, they can guarantee nothing if they utilize only standard Android sound path. That's the point expressed by Davy, which I (end user) fully support. UAPP is very special here because it also provides guaranteed bit perfect playback for streaming services, even for those which have official music players.

    I hope I explained the vision of HiBy DTA from end users and software developers point of view enough :) I remind you that iBasso has implemented even more than DTA in DX100 and then (iBasso extended AudioFormat for 24 & 32 bits and DTS), but they never created a noise around it, understanding that it does not really matter for end user.

    @Joe Bloggs, I hope you understand that no hurt was intended, it's only explanation of a vision.
    @Davy Wentzler, sorry if it was partially off-topic - I quit.
  9. digititus
    I would just like to add that my cheap Chinese tablet and phone are working just fine with UAPP with default settings. If @Davy Wentzler would like to know which devices, I'm happy to PM them for you to add to your list of compatible android devices.
    Last edited: Oct 24, 2019
  10. BobSmith8901
    Strange--I was just going to post a similar comment.

    I bought an inexpensive tablet to replace an older Tegra Note 7 (that I still use in UAPP/USB set-up w/ a Meridian Explorer2 and amp strapped on, but can only realistically be used in this single-use mode). I ended up buying an Acer Iconia B3-A40 10.1 inch that has the MTK MT8167 quad-core Cortex A35 1.3 GHz processor and 2Gb RAM.

    So far no problems and it's pretty peppy doing multitasking.

    Of course one of the first apps I had to install was my copy of UAPP w/MQA add-on. Just for s_its and grins I thought wth, lemme set up UAPP in bit perfect mode and select the hi-res driver and see what happens.

    Well, I was pretty floored. I went into Tidal and selected a 16/44.1 file and it showed Direct (not Android) and played the file perfectly. I couldn't believe it, this low cost tablet has, at least what UAPP recognizes as, a Hi-Res driver. I then put on a Tidal MQA file and played it in MQA mode, doing the first unfold just like it's supposed to, little green or blue light. Sounded great, but these tablets don't have a lot of volume--enough to enjoy though with a pair of hi-sensitivity Senn PX-100s.

    I thought, OK, let's see if the standard USB set-up works. Yep, hooked it up to my iFI Nano BL via USB and it recognized the DAC and I had the full masters unfold via the Nano, purple light and all.

    Edit: Re the HiRes driver for my Acer, after reading the hires direct driver explanation over on extreamsd.com I realize that my tablet may not actually be utilizing a HiRes driver and in fact may be not be playing through the direct audio path in spite of it showing "Direct". It could be choosing another non-direct path and not giving a failure at playback. l would have to verify by frequency analysis using android platform tools. So, take my above statement with a large grain of salt!
    Last edited: Oct 25, 2019
  11. Skepsis
    Hi, Davy,

    I am a long year UAPP fan (with my old OnePlus 3T and tried it also with OP 6 of my son). In the last Year I didn't even need my the LH GeekOut Infinity v2 USB, because after tweaking the internal Hires parameters the SQ with the builtin DAC is sufficiently good without an extrernal DAC.

    Just some observations and one "request":

    In contrast to the recommendation to set the HIRes driver audio format to auto, I coud get markedly better sound with fixed bit depth of 32 - at the cost of battery consumption, which I am willing to pay for it. Just with this is now on par with the HiBy SQ (and also battery drain).
    This is interesting, because the builtin Snapdragon WCD9xxx DAC officially only supports 24 bit (but obviously doesn't reject 32 bit input).

    Is there an explanation for it? (My best guess: internally takes places a conversion to 32 bit which is of lower quality than the algorithms of UAPP). This observation could be important, when this is valid for all of the WCD9xxx of the many Snapdragon SOCs.

    I also found upsampling to a multiple of the input is definitely beneficial for SQ. With my RME Babyface on PC it is even displayed by the performance indicators, that such an upsampling takes place internally within the DAC if it is fed with a lower sampling rate input.

    Another previous observation with external DACs: by attaching an external power supply (by attaching the DAC to a good quality powered HUB) I got a night and day improvement, over a range of DACs I have tried. (This applied also to the PC USB - e.g. my RME BF became my best DAC, better than the DSD capable LH GOV2 with HQPlayer).

    To MQA:

    a.) I don't see why the limitiation to BitPerfect with MQA playback is necessary, it makes the excellent parametric equalizer unusable. Only in connection with an MQA-capable HW seems this reasonable, but after having to convert it to PCM, a processing should be possible?

    b.) I cannot quite understand, how MQA (from Tidal) can sound so dramatically better than normal CD when playing it through the MQA AddOn (which I purchased). I would expect that the biggest improvement is in the BitDepth of 24 bit, and that is in the unfolded MQA with 24 bit isn't it ?
    If not so, shouldn't be rather 16 bit displayed while playing back without the AddOn? (With normal PCM files I couldn't make any big difference with higher sample rates, but very much with bitdepth over 16 bit.)

    And to my Request: I am using "Other Radio Stations" a lot as relatively good quality Classical and Jazz sources (the few broadcating in flac appear to vanish, but 320kb is often just enjoyable while travelling). Could You consider please to display the Meta Date of the just playing music, VLC player can do this also on Android?
  12. ratdog
    Does UAPP support Amazon HD?
  13. digititus
    Not yet
  14. Davy Wentzler
    Amazon does not have a public API and the streams are encrypted, so unfortunately not.
  15. taravasya
    Hello! I`d like to know your opinion...
    the developer of another player(Poweramp) claims that you are deceiving everyone, and supposedly the tracks from your player are down-sampled. In confirmation, he even brings some sort of screen from the terminal, looking at which, I would have to believe that downsampling is present.
    I repeat, I would really like to know the opinion of the UAPP developers on this matter. And most importantly, I would like someone more knowledgeable than me to be able to enter into a polemic if necessary, because personally it seems to me that just what Mr. MaxMP claims - this is a real lie...
    Last edited: Oct 25, 2019
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