Hey...

Jeg fandt lige nogle facts ang lyd med HDMI... Ved ikke om de står herinde, men der er en del godt stuff til eftertanke :o)

Har set en masse som snakker om Recievere som har 1,2 eller 1,3 eller som har HD lyd osv...

Så håber I ka bruge det her til noget...

(Er godt nok på engelsk)

We already know that HDMI is very misunderstood and when people have questions regarding HDMI (which are often asked prior to parting with money), are often not being given the correct answers. We have already produce a basic guide to HDMI which many of you have found helpful (this is available to download from the FAQ section in the cables forum).
However, this guide does not bring up many points regarding HDMI v1.3.

The main differences between HDMI versions are summarised below:

HDMI v1.0 supports video (up to 1080p) and audio (using PCM or AC3 or DTS bitstreams)
HDMI v1.1 supports as v1.0 but also supports the transport of MPL (Audio DVD digital data)
HDMI v1.2(a) supports as v1.1 but also supports the transport of DSD (SACD digital data)
HDMI v1.3 supports as 1.2(a) and has the following additional support:
Deeper colour - potential to transport up to 48 bit colour depths
Alternative colour space - potential to carry the xvYCC colourspace
Automatic Lip-sync adjustment - potential to automatically sync audio to video
Higher video resolution - potential to transport up to 1440p video signals
HD Audio Bitstream - potential to carry the digital bitstreams from Dolby and DTS HD audio formats

You will notice that in all of the cases above the differences between the versions are all quoted as what they can POTENTIALLY offer - NOT what having a device with HDMI v1.3 can actually provide. It’s
essential that people realise that just having a product with HDMI v1.3 does not mean they will get better video or sound! Perhaps the best example of this is the video resolution potential. Everyone is
talking about 1080p. 1080p is now regarded as the pinnacle of HD video (that’s another issue though!). No one would suggest that by having a device with HDMI v1.3 that you automatically increase your video resolution to 1440p - but will assume that having a device with HDMI v1.3 will mean they do get auto lip-sync, do automatically get higher colour depths and do automatically get the ability to carry HD audio bitsteams - NONE are true. HDMI v1.3 just means the cable could carry this data if it’s available and if both source and sink (receiving device) can handle it.

HDMI v1.3 is very much ahead of the technology that will be using it. To date, no displays can use xvYCC colourspaces (although Sony have recently announced a 70" $30,000 screen) just RGB or YUV, and no displays can use more than 24bit colour. These facilities have been allowed for in v1.3 for future use.

One of the most talked about and consequently most misunderstood improvement is the ability for HDMI v1.3 to carry HD audio bitstreams.

Dolby and DTS have both each recently announced two new HD audio formats Dolby's are Dolby Digital Plus (a lossy format) and Dolby True HD (a lossless format) DTS have released DTS HD (lossy) and DTS HD Master Audio (lossless). These formats are stored on the discs (either HD DVD or Bluray, but NOT standard DVD’s) in a compressed format. The name of the format is the compression system that is used in each case (ie, Dolby True HD uses Dolby True HD compression). For us to hear compressed data, two processes must happen. The first is the data must be decompressed (using a decoder). The second is the data must be converted to analogue (using DAC’s). Once both these processes have happened, we can hear the audio.

In order for these processes to happen, we need two devices, a decoder and a DAC (Digital to Analogue Converter). These devices can either exist in an AV amp, or the HD DVD/Bluray source or both. If both have decoders, only one of these devices will be used - a bit like if a CD player is connected to an amp with an optical cable, we would be using the DAC in the amp and the players DAC would not be used.

With HD Audio, we have three possible connection methods to allow the audio data to be heard. We can not use optical or coaxial digital connections at all, due to the bandwidth requirements of these formats.

The first option is to transfer the HD audio bitstream from source to amp.
This means the following is required; HD audio, HDMI v1.3 source (ie Bluray or HDDVD, an HDMI v1.3 repeater equipped AV amp with HD audio decoder and an HD disc which does NOT restrict bitstream transfer (almost none exist!)

The example above shows how most people believe HD audio will work. And it may do at a later date, but currently, film studios are requesting that all discs be authored in Advanced Content Mode. This will prevent the HD audio bitstream from being output from the HD player, rendering HDMI 1.3’s ability to carry this data as useless. This means another transfer method is needed as this example will not work for most HD DVD or Bluray discs. It's also worth mentioning that at the moment there are NO players capable of a bitstream output (due to their hardware), so even if the disc allows, the current players physically can not do it.
The next method is the standard most people will need to use - most interestingly and importantly, it requires HDMI v1.1 - version 1.3 is NOT required:

This method uses a single HDMI connection to carry the HD audio data to the amp. The HDMI cable carries digital data, so the amp’s DAC’s are used to convert this digital data to analogue. The
reason the HD audio can be transferred using HDMI v1.0 is that the player, knowing it can not output the HD bitstream, uses another popular digital transfer method instead - PCM(multi channel). This does not result in any quality loss, just simply means the data is transferred differently. The player actually decodes the data so there's no need for the amp to have HD audio decoders either.

The final method of transfer is to use the player to both decode and convert the digital data to analogue. This then requires one cable per audio channel (typically 6 or 8) to carry the signals from player to the amp. The player must also have the facility to output multi channel analogue signals and the amp you use must also be able to accept them. Most amps can, but are unlikely to be able to add any processing to these signals. For this reason, the digital transfer method tends to be preferred, especially when you consider that these HD formats are currently only 6 channel, so to use 7.1 systems would require post processing such as PLIIx).

Realistically, the only feature that HDMI v1.3 can make use of at the moment and in the near future is the auto lip sync feature, which would require source or repeater, and sink to be HDMI v1.3 and compatible with that feature. All the other features possible to carry via HDMI v1.3 are a way off yet.

Even so, you will find that manufacturers all start using HDMI v1.3 on their products to ensure the latest specs are adhered to but don't worry if your amp doesn't support it just yet! Your far better off worrying about features and quality of a product rather than the version of HDMI that it's using.

Mvh Patrick... 

 

Fedt, godt med lidt facts!

Jeg kan ikke helt finde ud af om HDMI 1.0 er nok til at overføre HD-DTS til forstærkeren eller ej?

Øverst står der:

"HDMI v1.3 supports:
HD Audio Bitstream - potential to carry the digital bitstreams from Dolby and DTS HD audio formats"

Mens man nederst kan læse:

"The reason the HD audio can be transferred using HDMI v1.0 is that the player, knowing it can not output the HD bitstream, uses another popular digital transfer method instead - PCM(multi channel)."

Jeg går ud fra det er to forskellige ting, men er stadig ikke helt med?

Svend P skrev: Jeg kan ikke helt finde ud af om HDMI 1.0 er nok til at overføre HD-DTS til forstærkeren eller ej? Øverst står der: "HDMI v1.3 supports: HD Audio Bitstream - potential to carry the digital bitstreams from Dolby and DTS HD audio formats" Mens man nederst kan læse: "The reason the HD audio can be transferred using HDMI v1.0 is that the player, knowing it can not output the HD bitstream, uses another popular digital transfer method instead - PCM(multi channel)." Jeg går ud fra det er to forskellige ting, men er stadig ikke helt med?

Forskellen ligger i om man vil overføre den dekodede PCM bitstream eller den "rå" DTS HD bitstream. Vil man gøre det første er v1.0 nok, men kræver en afspiller der kan dekode DTS HD. Det andet kræver både en afspiller der understøtter v1.3 OG en forstærker der kan dekode DTS HD. Det gør ingen forskel for lydkvaliteten om dekodningen sker i afspilleren eller forstærkeren.

Der har iøvrigt været spekulationer omkring hvorvidt discene vil være "låst" sådan at dekodningen SKAL foregå i afspilleren.

Jamen det vil da så umiddelbart sige, at hvis man er totalt ligeglad med billede-upscalering osv., så er HDMI 1.0 nok til DTS-HD?! Det er vel ikke helt utopisk at forvente at der kommer afspillere der kan spytte det ud i det rigtige format?

Hej Svend P

Svend P skrev: Jeg kan ikke helt finde ud af om HDMI 1.0 er nok til at overføre HD-DTS til forstærkeren eller ej?

Der er to muligheder:

• Afspilleren dekoder Dolby TrueHD eller DTS HD fra filmen, og sender det videre til forstærkeren via HDMI (uanset version) som PCM
• Afspilleren sender Dolby TrueHD eller DTS HD fra filmen videre til forstærkeren via HDMI 1.3, og lader den dekode det.

PCM er ukomprimeret digital lyd op til 8 kanaler (så det kan bruges til 7.1)

Bemærk dog, at surround forstærkeren stadig skal have mulighed for at modtage PCM via HDMI. Og som PCM 7.1, hvis det skal kunne bruges til de nye lydformater.

For tiden er der stor fokus på forstærkere som kan modtage og dekode Dolby TrueHD og DTS HD, men dekodningen kunne ligeså godt ske i afspilleren. Der kan være fordele ved at lade afspilleren stå for dekodningen, og det er at producenterne af film bedre kan udnytte pladsen på skiven. For afspilleren kan mixe kanalerne.

Eksempel:  En film udgives med DTS HD. Men producenten vil gerne have både tysk, fransk og italiensk tale - sammen med den engelske. Men 4x DTS HD lydspor vil fylde godt op på på disken. Istedet kan de lægge 4x center kanaler, en for hvert sprog, og lade de øvrige kanaler være rent musik og lydeffekter som ens for alle. På den måde kan afspilleren mixe 7.1 lyden i de fire sprog ud fra blot 11 lydkanaler, fremfor 24 lydkanaler hvis hvert sprog skal have sig egen plads.

Hvis den måde at udgive film på bliver almindelig, så får mere vi brug for dekodning i afspilleren frem for i forstærkeren, og det er nok at investere i en forstærker der kan modtage PCM 7.1 via HDMI. Og man kan glemme HDMI 1.3 i den sammenhæng.

HDMI 1.3 kan dog noget andet smart, med automatisk lipsync (synkronisering af billede+lyd) så den kan muligvis være nyttig på det område.

En 3. mulighed jeg ikke omtalte, er at lyden også kan være analog. Altså at afspilleren dekoder Dolby TrueHD eller DTS HD, og sender det over til forstærkeren som analog 5.1 (downmixet) eller som analog 7.1.

  /Lars

PS. Jeg er ikke selv ekspert på området - er selv igang med indlæringen 

 

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recordere.dk - AV Nyheder, Anmeldelser og Debat

Hvordan finder man så ud af om den kan modtage PCM over HDMI? Hvis man kigger på eks. Sony STR-DA7100

http://www.sony.de/view/ShowProduct.action?product=STR-DA710 0ES

Så har den bare "HDMI", så jeg gætter på det er version 1.0, da forstærkeren er fra 2005. Men hvor ser man om den tager 7.1 PCM? Det var der vel næsten ikke tænkt over da den kom frem?

Jeg har googlet det, og kan se at på nogle fora, skriver de at den kan. Men det er jo ikke ligefrem en garanti

Svend P skrev: Hvordan finder man så ud af om den kan modtage PCM over HDMI?

Manualen er normalt det bedste bud, på den type detaljerede oplysninger.

Den skriver at der kan modtages PCM via HDMI, men oplysningerne i manualen er lidt sparsomme. Som du siger, der var nok ikke så stor fokus på den dengang den kom frem.

  /Lars

__________________
recordere.dk - AV Nyheder, Anmeldelser og Debat