Re: HDMI vs USB

On Tue, 09 Feb 2021 15:07:40 -0500, Paul <[email protected]>
wrote:

>[email protected] wrote:
>> For a variety of reasons,  the  Smart TV  features  on my 43 inch LG
>> are a royal PITA  -  I've been using my laptop  and connecting to the
>> TV with a  Display Port=HDMI cable.   The TV also has  USB sockets  -
>> is there any  significant difference in quality  between  HDMI and USB
>> cables  when used  for this  ?   I'm considering buying a  longer
>> cable  HDMI=HDMI    for my wife to use with her new laptop.
>>  I did try a google search but got lost-in-the-weeds.
>>   Thanks   John T.
>>  
>
>Ports can do many things.
>
>All I can do in this case, is cite a typical case.
>
>USB is used for USB Mass Storage, and for the connection
>of a USB flash drive containing movies or photos. The
>TV can play these.
>
>DisplayPort and HDMI are for the carriage of video signals.
>The quality is only as good as the source. If the source
>upscales content recorded at low-res, then the picture
>looks like shit.
>
>If you had Netflix 4K (making up an imaginary service),
>then they would try to play movies recorded in 4K and
>having a healthy dollop of content. These should play
>nice when connecting the computer with the Netflix session,
>via cable, to the TV set HDMI or DP inputs.
>
>Other ways to play Netflix, would be if the TV set has
>a "Netflix.app" and then, again, a healthy dollop of
>4K content is shipped down the Ethernet wire (or Wifi)
>as packets, and makes a decent quality picture.
>
>If the Internet service does not have sufficient bandwidth,
>Netflix may detect this, and send lower resolution content,
>which when upscaled, doesn't look as good.
>
>If the TV set has multiple HDMI connectors, then you
>may be able to connect more than one computer, then switch
>to a particular TV port and display the signal coming from
>it. This allows switching from your output, to the output
>the laptop of your wife provides.
>
>The Wikipedia HDMI and DisplayPort articles, describe the
>resolution and refresh limits of the various HDMI and
>DisplayPort standards versions. The source equipment
>and the destination equipment both have limits, and
>the common denominator is what they can use to talk to
>one another. Not all computers can drive a TV set
>at the highest rate desired.
>
>And generally this doesn't make too much difference to the
>cables. There can be quality differences between cables,
>which affects the maximum length possible while using them.
>The standards are not specific enough to recognize the
>difference. You might guess that a six foot cable would be
>OK, while stringing 30-50 feet of cable, and doing 4Kp60
>might result in colored error snow on the screen. The cables
>have attenuation, and if the cable is long enough, and the
>signal is a high enough frequency, the receiver diff pair
>can no longer slice the threshold and extract digital bits
>from it.
>
>Summary:
>
>1) Keep cable short. Don't be an idiot. Don't run signal
>    from attic to basement. Cable (HDMI or DP) will likely be
>    OK when sitting on the couch and in front of the TV.
>    Six foot cable should be OK. Fifty foot cable, less so.
>
>2) When using computers for drive, the image is only as
>    good as the resolution of the content. Upscaling
>    720x480 content to fill a 4K screen, is not going to be
>    all that good.
>
>3) The same goes for a movie stored on a USB stick.
>    4K movie plays at 4K. Low res movie upscales too much
>    to look nice. If you store a DVD movie on a USB stick,
>    think about what it's recorded as (720x480 ?).
>
>4) TV sets have internal "Apps", like Roku. In these cases,
>    the Internet site has to source nice 4K content, ISP
>    is required to not throttle the packets (so the playback
>    isn't jerky). Then, it might just work. The signal in this
>    case, flows over the TV set Ethernet cable or the TV set
>    Wifi interface to your home router that has Wifi.
>
>    Paul


  Thanks for the detailed reply  Paul.

 <  but you lost me in the weeds  !    not your fault >

I've done some more reading  and discovered that
  USB  or   HDMI    are more than just a cable conduit
for digital info  ....     which was the basis for my query.

 So  -   
 -  given  -  a laptop source for  audio-video content - 
          -  and - a -
 -  given   smart TV  receiving  that content  -

Q.   will the use of a HDMI cable  improve the results  -
   compared to  using  a   USB  cable  ?

No long distances are involved  -  12 feet  or so.  

   John T.