Why feed video thru surround amp ?

[RobinKidderminster]

I dont have a HDMI input to my surround amp but I use optical inputs for DD sound. Is there something I've missed because i see no reason to put video inputs thru the amp.

Cheers all

 

[professorhat]

Well, with HDMI of course, you want to feed that into your amp in order to get HD audio.

However, with other connections, it can be useful to route everything into the amp as you can then use this as the main switching unit with just one cable (or just a few at least) going from the amp to the TV. Correctly setup, it means when you switch your amp to the correct input, you get both the correct sound from the speakers and also the correct picture on the TV i.e. you save a step on having to change the TV's input. Some amps also offer the ability to delay sound etc. as well making it easier to ensure lip sync works properly.

 

[RobinKidderminster]

Thank you prof. I had thought about the lip sync but I'd not thought about the switching.

Mmmm - sometimes the simplest things elude one

Cheers

 

[The_Lhc]

RobinKidderminster: Thank you prof. I had thought about the lip sync but I'd not thought about the switching.

Mmmm - sometimes the simplest things elude one

I'd suggest that getting the HD audio is a more important reason for using HDMI than simply video switching. You can't get HD audio through optical or coaxial digital connections.

 

[d4v3pum4]

Most AV Receivers/amps can be considered to be the hub of an AV setup. If you have several sources using the same connection e.g. component video or HDMI, you can run the video via the amp and run a single cable to the TV. Also on newer models, they can upconvert analogue sources (composite, s-video, component video) to HDMI resulting in a single cable to the TV. Some older amps would only upconvert composite video and s-video to component. Upscaling (changing the resolution from one to another) in amps is filtering down all the time to lower priced models but as the scalers fitted in budget receivers aren't much better than the ones found in your TV or source, it is often considered best to leave these to do the scaling. Obviously if you have a higher end amp with a beefy scaling chip, you can use that to scale the image to a suitable resolution e.g. 1080p.

Also note that HDMI also carries video (new version of SCART) so if you want to extract the audio from HDMI, you have to route the video via the Receiver/amp.

My own amp doesn't have HDMI but I do have an external HDMI switch/splitter so that I can feed 3 HDMI sources into 1 and then split that single output to my projector and TV. If I had an AV Receiver with 4 HDMI inputs and 2 outputs, I could do away with these altogether.

Presumably you don't have multiple sources using the same connection type or you have sufficient inputs on your display? If you do and don't need HDMI audio, your present amp is more than sufficient for your present needs.

 

[RobinKidderminster]

O heck !! And i thought I knew a little about HiFi.

OK - humour me. What is the difference between HD audio and Dolby Digital. I know the latest formats such as Dolby True etc are not supported by my amp. I guess this is what you mean but I'm surprised that these formats are not available thru optical/digital outputs.

Thanks again for your feedback

 

[professorhat]

Very simply, it's the bitrate - the new formats are lossless like Apple Lossless and FLAC in the music world, compared to lossy formats like Dolby Digital / DTS which are equivalent of MP3 i.e. as the soundtrack is made and compressed, data is thrown away to fit them on the disc. Like the music equivalents, Dolby TrueHD and DTS HD Master Audio soundtracks therefore sound better as more detail is contained within the soundtrack.

HD audio formats are only available on Blu-Ray (or HD-DVD) at the moment as this has the space needed to contain these soundtracks. Optical and Digital coax don't have the required bandwidth to send these formats, this is why you need an HDMI connection to send them digitally (or the Blu-Ray player can convert the signal to analogue and send them out via multichannel outputs if it has them).

 

[d4v3pum4]

HD audio is lossless. This guide might explain

 

[RobinKidderminster]

Wonderful - thankyou folks. When I get my blu-ray I will invest in a HDMI amp. I'll put up with optical till then.

I am very grateful for these detailed replies.

Kind regards

RobinKidderminster