[mightymouse2045]

There is no FLAC passthrough.
http://www.avsforum.com/t/1376533/faq-on...gh-reclock

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.

Here for example is from my Yamaha RX-V3067 receiver:

•HDMI
Dolby Digital, DTS, DSD 6ch, Dolby Digital Plus, Dolby TrueHD,
DTS-HD, PCM 2ch-8ch

This includes the following decoders:
Dolby TrueHD, Dolby Digital Plus, Dolby Digital,
Dolby Digital EX, DTS-HD Master Audio,
DTS-HD High Resolution Audio, DTS Express, DTS,
DTS-ES Matrix 6.1, DTS-ES Discrete 6.1, DTS 96/24


The rest are all under Network:

•USB (USB1.1 Full Speed) ................................................................. 1
Audio Format ................ MP3, WMA, WAV, MPEG-4 AAC, FLAC
Max Audio Support fs................................................. 48 kHz/24 bit
• Ethernet (100Base-TX/10Base-TX) .................................................. 1
PC Server
Audio Format.............. MP3, WMA, WAV, MPEG-4 AAC, FLAC
Max Audio Support fs .............................................. 96 kHz/24 bit
•DLNA
Version ............................................... 1.5 (DMP & DMR support)
Audio Format ............. MP3, WMA, WAV, MPEG-4 AAC, FLAC
Max Audio Support fs...............................................96 kHz/24 bit

So yes you're correct, PCM over HDMI, USB & Network for FLAC (ie with the receiver opening the file directly itself).

[garfield]

In case the device running KODI connected directly to a TV which is connected to a multichannel AV receiver via HDMI passthrough or HDMI ARC, it is impossible to reproduce more than two channels of PCM audio because computer operating system gets audio capabilities info from the TV via HDMI EDID and outputs accordingly. Most TVs are just 2.0.

So it becomes impossible to listen to multichannel FLACs or DSDs and even to DD and DTS preconverted to PCM by KODI as the computer's audio driver outputs any multichannel PCM audio downmixed to just 2.0 in case it recognizes 2.0 only support by the output device, no matter it passes the audio signal directly to a multichannel one.

So it is possible to get multichannel audio only if it is bitstreamed directly to AV reciver as is. That's why bitstreaming FLAC and other formats is currently required.

[da-anda]

why not directly connect the KODI device to the AVR? The AVR certainly should have more than one HDMI in. Also, you should be able to passthrough AC3/DD and DTS working since these only require two channels, but you have to enable passthrough for them and set the speakers to 2.0 in KODI. And if you enable AC3-transcoding you will also get 5.1 from FLAC and AAC to the AVR, but unfortunately not as bitstream but re-encoded to AC3. It's basically like SPDIF on old non-HDMI AVRs

[jjd-uk]

bitstreaming FLAC

FLAC is not a format that can be bitstreamed thus it is always sent as LPCM

[garfield]

why not directly connect the KODI device to the AVR?

There could be many reasons. 4K TV and FHD receiver for example. Or extremely long connection cable from TV to the receiver that damage the picture but plays the sound.
 

FLAC is not a format that can be bitstreamed thus it is always sent as LPCM

That explains a lot ))

[koawmfot]

bitstreaming FLAC

FLAC is not a format that can be bitstreamed thus it is always sent as LPCM 

can you please explain why it is not?  not challenging the comment, i really really want to understand what the possibilities are and what the limitations are and where they come from.... if you don't mind explaining a little.  thanks///

[jjd-uk]

bitstreaming FLAC

FLAC is not a format that can be bitstreamed thus it is always sent as LPCM 

can you please explain why it is not?  not challenging the comment, i really really want to understand what the possibilities are and what the limitations are and where they come from.... if you don't mind explaining a little.  thanks///

The simply answer is that HDMI does not support transmission of FLAC audio. While some AVR's will state support of FLAC in their specs, this will only ever be via USB or via ethernet using it's own built in player software and never the HDMI.

The longer answer is that all audio passed by HDMI uses the IEC61937 standard and FLAC is not a supported format within this standard. The likely reasons for this is FLAC does not have a big corporation behind it promoting it in the manner that Dolby and DTS would do with their formats. In truth however only the source device needs to support decoding and then pass the audio as a LPCM, this is because as all audio must end up in the PCM format anyway, as that's what Digital to Analog Converters work with in order to send audio to the amplifiers and then the speakers. So it's just a question of where that decoding to PCM takes place, taking TrueHD as an example, it should not matter if it's decoded in the source device and sent over HDMI as LPCM to an AVR, or whether it's sent as TrueHD and then decoded in the AVR to PCM, as in the end the exact same PCM stream of data should end up at the DAC's. So the absence of FLAC from IEC61937 is a complete non-issue as it MUST eventually end up as PCM at some point in the chain.

[koawmfot]

The simply answer is that HDMI does not support transmission of FLAC audio. While some AVR's will state support of FLAC in their specs, this will only ever be via USB or via ethernet using it's own built in player software and never the HDMI.

The longer answer is that all audio passed by HDMI uses the IEC61937 standard and FLAC is not a supported format within this standard. The likely reasons for this is FLAC does not have a big corporation behind it promoting it in the manner that Dolby and DTS would do with their formats. In truth however only the source device needs to support decoding and then pass the audio as a LPCM, this is because as all audio must end up in the PCM format anyway, as that's what Digital to Analog Converters work with in order to send audio to the amplifiers and then the speakers. So it's just a question of where that decoding to PCM takes place, taking TrueHD as an example, it should not matter if it's decoded in the source device and sent over HDMI as LPCM to an AVR, or whether it's sent as TrueHD and then decoded in the AVR to PCM, as in the end the exact same PCM stream of data should end up at the DAC's. So the absence of FLAC from IEC61937 is a complete non-issue as it MUST eventually end up as PCM at some point in the chain. 

awesome thanks so much for the response, this is the first clear answer on this i have seen since starting to look.  really appreciate it.

[CrazyDwarf]

With regard on quality there is ZERO advantage in passing through an encoded audio stream. It does not matter on what side decoding is done because decoding itself has no impact on quality. As long as no resampling or rematrixing is required it's still bitperfect when outputting PCM.

Hi, thank you for that reply. So, basically, if the sample rate of the FLAC is 44.1 kHz for example, and it is played through KODI on a PC that is connected to the AVR through HDMI, Output set to WASAPi AVR, and resampling to best match - receiver audio signal shows information about signal as PCM 44.1 khz. Does that mean, that audio was not decoded - then reencoded or resampled again and that it is not bitperfect? I mean, I do not hear the difference but I like it when I play from receiver and my home media server, it shows FLAC. But, anyway, if that is true - then it is great.

[black_eagle]

Does that mean, that audio was not decoded - then reencoded or resampled again and that it is not bitperfect?

It means that Kodi has decoded the audio to PCM and then sent that decoded stream to your AVR.  No, it has not been resampled or re-encoded and it will be bit perfect when it arrives at your AVR.   Anyway, the end test is not what you see on a screen or a display but what your ears tell you.