Hi guys. Please advise me if you have any further questions you want to be added. Thanks.1) What are unpacked audio (or raw PCM) or lossless and lossy audio formats?Uncompressed (unpacked):
PCM, is an exact replication of the studio master, encoded on disc without compression. The benefit to this is that it maintains the purity of the source without any loss of fidelity that may come from compression. This should be expected as is, i.e 96/24 for multichannel, 192/24 for stereo.
However, you may find out such as a kind of PCM on DVD-Audios and SACDs, not on BluRays since it takes too much space on the disk. Most of the time i found only 48/16 or rarely 48/24 PCM on BluRays which means it is down-sampled studio master replication (not compressed but down-graded).
And if a BluRay contains both PCM and any lossless audio (THD or DTS-Master) together, I would prefer second one since it is always 96/24 and once you decode it, you get a 100% identical copy of the original PCM.Lossless:
Dolby TrueHD or DTSHD Master is a "lossless" compression codec. Although it is compressed to take up less disk space than a PCM track, once decoded it is a bit-for-bit identical to the studio master (at either 16-bit or 24-bit resolution, at the discretion of the studio). It may help to think of it like a ZIP file that holds a PCM track. Once you unzip the file, you get a 100% identical copy of the original PCM, without compromising any sound quality.
BTW flac is an unofficial lossless format.
OK, if I (as rica) have a DTSHD-Master audio , I directly bitstream it to my AVR, but if I have a THD, either I bitstream directly to my AVR and increase the volume level much higher or extract it with madshi's eac3to and remux to a flac mkv so as to get rid of Dolby's "dialog normalization" and leave my AVR's volume level where it has already been.
You will find a perfect article here by Joshua Zyber:http://www.highdefdigest.com/news/show/1233
And most of the explanation here is quoted word by word from his another article, thanks Joshua, btw:http://www.highdefdigest.com/news/show/1064Lossy:
For HD: Dolby Digital Plus, DTSHD-HR
For SD: Dolby Digital, DTS
Those are all compressed lossy formats, for more information pls check out Joshua's article.2) What is bitstreaming, what is bitperfect (bitexact) or non-bitexact pass-through streaming?Bitstreaming:
You pass lossless or lossy audio formats directly to your AVR. (without decoding them.)
Your AVR will decode it of its own decoder and convert this decoded digital PCM to analog PCM over its DAC. If you select "direct or pure" mode of your AVR, it wouldn't touch the audio for post-processing like adding some effects or down-mixing/up-mixing. In this case decoded and converted (to analog) audio will be transmitted directly as is (bitperfect-bitexact) to the AVR's amplifier.
If we are talking on bitexact bitstreaming, we should consider lossless formats only, bitexact bitsreaming of lossy formats is nonsense in this case.Pass-through streaming:
You may pass directly unpacked PCM or decode lossless or lossy formats inside PC via a SW decoder and convert them to analog (over onboard DAC or SB's DAC) or pass as a digital PCM to your AVR's DAC to be converted to analog and amplify later.
Raw or decoded streams, even haven't been touched by a decoder, finally drop into windows' mixer to be down-sampled or up-sampled if we use windows' renderers like direct sound or wave out.
In this case windows' mixer always interfere with the decoded audio. (wasapi shared mode)
Alternatively you will bypass windows' mixer via Wasapi exclusive mode.
In this case windows's mixer cannot interfere with the decoded stream. (wasapi exclusive mode.)
But there are two options which have to be chosen here:
Bitexact. (it should stay as bitexact in AVR as well.)
Or non-bitexact.3) What is Wasapi exclusive?
Windows introduced a new audio driver starting with Vista: WASAPI (Windows Audio Session API). This is a low latency driver.
WASAPI gives two options for audio rendering - Shared mode and Exclusive mode.
mode, you are the only application talking to the audio endpoint in question - all other applications cannot make any noise. This gives the absolutely best performance possible. This means audio is bypassing Windows' mixer.
As WASAPI in exclusive mode talks straight with the driver of the audio device, the stream sent to this device must match the capabilities of this device in terms of bit depth, sample rate, number of channels and audio format (mostly PCM) otherwise it is silence. You always get automatic sample rate switching using WASAPI exclusive.
mode, windows' mixer will interfere with audio, which means the main stream will share the endpoint with other applications. In other words, you can still hear Windows sounds, etc.
While using it in shared mode, you must either hope that the Vista machine's audio engine is set to the exact sample rate of your audio, or it will downsample if mixer set up already 44 instead of 48 (or 48 instead of 96)
However, bypassing Windows Mixer typically results in lower
latency between decoding/rendering and output, though Windows allows low
latency playback through WASAPI shared mode without bypassing the mixer.
source: http://mark-dot-net.blogspot.com/200...th-wasapi.html4) Why and when we need Wasapi exclusive?Do we need wasapi exclusive in bitstreaming?
No, because Windows' mixer can not interfare with compressed formats, so you can directly pass compressed audio over SPDIF(for SD lossy formats) or HDMI(for HD lossless or lossy formats and SD lossy formats.) to your receiver to be decoded there. (via appropriate decoders which are able to pass compressed stream to the end-point.)Do we need Wasapi exclusive for pass-through?
Yes you will need it for sure in this case. I mean if you have a raw PCM or decoded compressed stream to PCM in your hand.
(As stated before even flac is a lossless format, it can not be bitstreamed; you should decode it in your HTPC since no contemporary AVR is able to decode it.)
Originally Posted by vladd
As mentioned earlier in the thread, FLAC can only be decoded by AVRs (that support it) when playing a file directly from a USB device or the network. Even then, it must be an audio only FLAC file (no video like in an MKV container). It is not possible to bitstream FLAC because there is no specification that supports FLAC bitstreaming via SPDIF (which probably couldn't support more than 2 channel anyway) or HDMI. Even if the AVR could detect and decode FLAC via HDMI, there is no way to output it in bitstream format from the HTPC.
Windows' mixer always tries to interfere with raw pcm (or decoded audio to pcm) and try to down sample or up sample it.
To avoid the mixer interferes with the audio, we should select Wasapi exclusive mode in ReClock.
You may overcome Windows's mixer selecting one of these different options:
1) You can pass-through stream over ReClock as non-bit exact streaming,
2) You can pass-through stream as bitexact(bitperfect) over ReClock.
In this case, we should consider unpacked PCM or lossless formats. Bit exact streaming of lossy formats is nonsense sure.5) How do we understand we are streaming pass-through in wasapi exclusive mode or shared mode?
Easy to understand:
1) While playing your media, just play with Windos's mixer's volume slide bar. If the volume is increasing or decreasing, you are in WASAPI shared mode.
2) Just try to play any windows sound while playing your media. If you hear clicked Windows sound, you are still in WASAPI shared mode.
3) If you are in WASAPI exclusive mode, you will never hear any Windows sound or playing with Windows' mixer slide bar doesn't affect the volume level.
Or so as to make sure 100 percent:
6) What are the requirements for bitstreaming or pass-though streaming?
For further test:
Configure Window's mixer to worst quality:
Open sample mkv (96_24),
If you see on your AVR's info display (in my case menu > info > audio input signal)i it means WASAPI SHARED MODE
If you see this (assuming you leave the mixer config same as above), it means you are listening bitexact streaming; WASAPI EXCLUSIVE
Requirements for bitstreaming:
1) A media player which you can easily select your preferred filters like MPC-HC.
2) A splitter which is able to recognize all current containers lile m2ts, mpls, mkv and all lossless or lossy formats and split them truly like Lav Splitter. ( or MPC's gabest /matroska splitters together.)
3) An audio decoder which is able to recognize the compressed audio and pass directly to audio renderer. ( like LavAudio or FFDShow.)
4) Any audio renderer. (Wave Out is my selection in this case.)
For HD+SD audio bitstreaming:
1) Onboard Intel Clarkdale (HDMI 1.3) or Sandybridge (HDMI 1.4)
or nVidia card (which has HDMI 1.3 or HDMI 1.4 out.)
or AMD-Ati card (which has HDMI 1.3 or HDMI 1.4 out.) PLEASE see: http://www.avsforum.com/avs-vb/showt...3#post21525943
2) HDMI cable.
additional note : If you have an HDMI 1.3 compliant previous generation AVR in your hand you can bitstream HD audio formats to your 1.3 compliant AVR via an HDMI to HDMI cable while you are watching 3D BD ; i mean you cand send 3D video over DVI to HDMI cable (or DVI to HDMI adapter plus HDMI to HDMI cable) to your 3D ready PJ at the same time.
3) HDMI 1.3 or 1.4 compliant AVR. (It must be able to decode all current official HD or SD audio formats .ie, If your AVR is just able to decode DTSHD-HR, you can not decode DTSHD-MA. Or even flac is completely a lossless HD format, you can never bitstream it to any AVR because it is not official format and afaik
none of those current AVRs will accept it to decode or unpack. So it must be unpacked by a SW decoder inside PC.) Finally your AVR will decode compressed lossy or lossless format you bitstreamed, convert it to analog over its own DAC and amplify it.
For SD audio bitstreaming only:
1) Onboard SPDIF or Optical output,
or an external audio card which has SPDIF or optical output. (like Creative) ) (btw SPDIF is limited with 5.1 digital bitstreaming) (Is there any difference between onboard spdıf or SB's spdif? No.)
2) SPDIF or optical cable.
3) An AVR which has SPDIF/optical input. (It must be able to decode all official SD audio formats like ac3, dts) or an satellite speaker system for PC like Logitech or Creative.Requirements for pass-through streaming of unpacked PCM or decoded lossless or lossy audio (BITEXACT or NOT)
1) A media player which you can easily select your preferred filters like MPC-HC.
2) A splitter which is able to recognize all current containers lile m2ts, mpls, mkv and split them truly like Lav Splitter. (or MPC's gabest /matroska splitters together.)
3) An audio decoder which is able to decode compressed audio and pass directly to audio rendereres like LavAudio or ffdshow. (if your container is mkv, you can directly connect your PCM -raw or converted- audio to ReClock.) (comparing ffdshow with lav in passthrough streaming i'd raher choice lav since it automatically selects the right bitrate.)
4) ReClock adio renderer for both bitexact or non-bitexact wasapi exlusive streaming options.
For HD+SD audio passthrough streaming:
1) Any mobo which has onboard HDMI output for streaming digital PCM to your AVR. (Any version of HDMI; including HDMI 1.1 and 1.4.)
or any AMD-Ati /nVidia card which has any vesion of HDMI out.
2) Onboard or extrenal sound card's analog outputs. (Onborad DAC is not recommended since they are cheap devices.)
3) HDMI cable or analog cables.
4) Any AVR which has any version of HDMI input . (In this case AVR gets uncompressed PCM and convert it to analog over its own DAC and amplify it.)
or any AVR which has analog inputs or an satellite PC speaker system like Logitech or Creative. (they accept PCM previously converted to analog via DAC of mobo or sound card.)
For SD audio pass-through streaming only:
1) Onboard analog outputs: I wouldn't advise that since onboard DACs are very cheap ones.)
or analog outputs of an external audio card . (like Creative) ) (DACs of external cards always competitive with AVRs DACs.
2) Analog cables.
3) Any 5.1 AVR or an satellite speaker system for PC like Logitech or Creative.7) How to configure MPC, lav/ffdshow and ReClock for bitstreaming or pass-through streaming?http://forum.doom9.org/showpost.php?...&postcount=1888) Do i need bitexact pass-through or should i prefer non-bitexact pass-through with ReClock. (both are wasapi exclusive.)
It's up to you; even we use most modern GPUs with their current drivers, none of them gives the refresh rate 100 % properly.
If we don't touch ReClock's inline config, even it streams in WASAPI exclusive mode, we don't get bitexact streaming but we get most accurate video audio matching and no human ear can distinguish the difference.
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