Forum Jump: 
 33Likes
Reply
 
Thread Tools
post #1 of 121 Old 11-12-2018, 06:20 AM - Thread Starter
AVS Forum Special Member
 
sjm817's Avatar
 
Join Date: Apr 2007
Posts: 1,145
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 581 Post(s)
Liked: 227
OTA 1080i bitrate NBC Vs CBS

Now that I am doing OTA DVR, I made an observation when recording a few NFL games of 3 hr in duration. The NBC game had a significantly lower bitrate than CBS. I actually recorded 2 CBS games and they were both very similar ib size. Is this a normal difference between NBC and CBS or is it more the local broadcaster (DC market)? Im going to try ABC/FOX to see if there is a difference in 720P content as well.

WUSA CBS
Codec MPEG2VIDEO
Bitrate 13343 kbps
Bit Depth 8
Chroma Location left
Chroma Subsampling 4:2:0
Closed Captions 1
Color Range tv
Frame Rate 29.97 fps
Height 1080
Level 4
Profile main
Ref Frames 1
Scan Type interlaced
Stream Identifier 256
Width 1920
Display Title 1080i (MPEG2VIDEO)
Duration 3:05:01
File NFL Football (2002) - 2018-11-11 16 25 00 - Seattle Seahawks at Los Angeles Rams.ts
Size 17.87 GB
Codec AC3
Channels 6
Bitrate 384 kbps
Language English
Audio Channel Layout 5.1(side)
Sampling Rate 48000 Hz
Stream Identifier 257
Display Title English (AC3 5.1)

WRC NBC
Codec MPEG2VIDEO
Bitrate 9159 kbps
Bit Depth 8
Chroma Location left
Chroma Subsampling 4:2:0
Closed Captions 1
Color Range tv
Frame Rate 29.97 fps
Height 1080
Level 4
Profile main
Ref Frames 1
Scan Type interlaced
Stream Identifier 256
Width 1920
Display Title 1080i (MPEG2VIDEO)
Duration 3:09:57
File NFL Football (2002) - 2018-11-11 20 20 00 - Dallas Cowboys at Philadelphia Eagles.ts
Size 12.92 GB
Codec AC3
Channels 6
Bitrate 384 kbps
Language English
Audio Channel Layout 5.1(side)
Sampling Rate 48000 Hz
Stream Identifier 257
Display Title English (AC3 5.1)

WTTG FOX
Codec MPEG2VIDEO
Bitrate 7264 kbps
Bit Depth 8
Chroma Location left
Chroma Subsampling 4:2:0
Closed Captions 1
Color Range tv
Frame Rate 59.94 fps
Height 720
Level 4
Profile main
Ref Frames 1
Scan Type progressive
Stream Identifier 256
Width 1280
Display Title 720p (MPEG2VIDEO)
Duration 3:29:56
File NFL Football (2002) - 2018-11-15 20 00 00 - Green Bay Packers at Seattle Seahawks.ts
Size 11.59 GB
Codec AC3
Channels 6
Bitrate 448 kbps
Language English
Audio Channel Layout 5.1(side)
Sampling Rate 48000 Hz
Stream Identifier 257
Display Title English (AC3 5.1)

WJLA ABC
Codec MPEG2VIDEO
Bitrate 9548 kbps
Bit Depth 8
Chroma Location left
Chroma Subsampling 4:2:0
Closed Captions 1
Color Primaries bt709
Color Range tv
Color Space bt709
Color Trc bt709
Frame Rate 59.94 fps
Height 720
Level 4
Profile main
Ref Frames 1
Scan Type progressive
Stream Identifier 256
Width 1280
Display Title 720p (MPEG2VIDEO)
Duration 2:59:56
File College Football (2009) - 2018-11-17 12 00 00 - Ohio State at Maryland.ts
Size 12.72 GB
Codec AC3
Channels 6
Bitrate 384 kbps
Language English
Audio Channel Layout 5.1(side)
Sampling Rate 48000 Hz
Stream Identifier 257
Display Title English (AC3 5.1)

Last edited by sjm817; 11-18-2018 at 08:15 AM.
sjm817 is offline  
Sponsored Links
Advertisement
 
post #2 of 121 Old 11-12-2018, 12:45 PM
Advanced Member
 
reds75's Avatar
 
Join Date: Aug 2011
Posts: 530
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 135 Post(s)
Liked: 154
Life before sub-channels. The picture quality was so much better. I remember watching The Santa Clause movie with Tim Allen when it was first shown in HD. The detail in the picture was fantastic.
aaronwt, DrDon and zippyfrog like this.
reds75 is offline  
post #3 of 121 Old 11-12-2018, 01:12 PM - Thread Starter
AVS Forum Special Member
 
sjm817's Avatar
 
Join Date: Apr 2007
Posts: 1,145
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 581 Post(s)
Liked: 227
Oh yeah. Sub-Channels. All those SD channels that I hide/uncheck the boxes for after I do a channel scan!

Last edited by sjm817; 11-12-2018 at 01:15 PM.
sjm817 is offline  
Sponsored Links
Advertisement
 
post #4 of 121 Old 11-12-2018, 07:25 PM
AVS Forum Special Member
 
tylerSC's Avatar
 
Join Date: Jun 2010
Location: Mauldin SC, 29607
Posts: 6,200
Mentioned: 3 Post(s)
Tagged: 1 Thread(s)
Quoted: 1049 Post(s)
Liked: 212
In DC area you may also try to pick up Baltimore and see if any of those channels have better bit rate for video quality.
tylerSC is offline  
post #5 of 121 Old 11-12-2018, 07:38 PM - Thread Starter
AVS Forum Special Member
 
sjm817's Avatar
 
Join Date: Apr 2007
Posts: 1,145
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 581 Post(s)
Liked: 227
Quote:
Originally Posted by tylerSC View Post
In DC area you may also try to pick up Baltimore and see if any of those channels have better bit rate for video quality.
Im actually in Loudoun. I have an outdoor antenna that is directional and pointed at the DC towers. Cant really get Baltimore unless I redo the Antenna setup. Not a big deal. The bitrate was an interesting observation but not a real issue.
sjm817 is offline  
post #6 of 121 Old 11-12-2018, 08:49 PM
Advanced Member
 
speedlaw's Avatar
 
Join Date: Nov 2004
Location: New York, about 40 miles north of "New York"
Posts: 543
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 65 Post(s)
Liked: 48
Quote:
Originally Posted by reds75 View Post
Life before sub-channels. The picture quality was so much better. I remember watching The Santa Clause movie with Tim Allen when it was first shown in HD. The detail in the picture was fantastic.
Early in the ATSC days, while it was still cutting edge, I recall a reel that NJ public TV played in a loop, as a filler, HDTV programming being scarce at the time....

A cameraman took an HDTV camera to the boardwalk in Seaside. It was perfect, and just like you were there.

Short answer...it ALL looked like a blu ray.
aaronwt and BiggAW like this.

In Vienna we sit, in late night cafe. Straight Connection, on T.E.E.
speedlaw is offline  
post #7 of 121 Old 11-13-2018, 01:36 AM
AVS Forum Addicted Member
 
Trip in VA's Avatar
 
Join Date: Jun 2003
Location: Alexandria, VA, US
Posts: 16,200
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 1245 Post(s)
Liked: 420
Send a message via AIM to Trip in VA
Both WUSA and WRC are channel sharing with other broadcasters as a result of the Incentive Auction, but the terms are different.

For WRC, NBC owns both 4-1/4-2 and the associated Telemundo on 44-1/44-2. As such, they're running 2x1080i and 2x480i on the single signal. They're using variable bitrate encoding, and the common ownership means they're using a common pool. This means that if Telemundo happens to need more bandwidth than NBC at a given time, it could be that 44-1 takes 70% (for example) then there's 30% left for 4-1/4-2/44-2. The equipment attempts to balance as best as possible, and on average, that means that 4-1 and 44-1 should have about a 50/50 split as a general matter.

For WUSA, however, they're sharing with WJAL on 68-1. But they're not commonly owned, and they've arranged that WJAL can use exactly 25% of the channel 9 bandwidth. Additionally, during NFL, 9-2 gets turned off, so the full ~14 Mbps goes to 9-1.

There's your difference in size.

- Trip

N4MJC

Comments are my own and not that of the FCC (my employer) or anyone else.

RabbitEars

"Ignorance and prejudice and fear walk hand in hand..." - Rush "Witch Hunt"

Trip in VA is online now  
post #8 of 121 Old 11-13-2018, 05:57 AM - Thread Starter
AVS Forum Special Member
 
sjm817's Avatar
 
Join Date: Apr 2007
Posts: 1,145
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 581 Post(s)
Liked: 227
Quote:
Originally Posted by Trip in VA View Post
Both WUSA and WRC are channel sharing with other broadcasters as a result of the Incentive Auction, but the terms are different.

For WRC, NBC owns both 4-1/4-2 and the associated Telemundo on 44-1/44-2. As such, they're running 2x1080i and 2x480i on the single signal. They're using variable bitrate encoding, and the common ownership means they're using a common pool. This means that if Telemundo happens to need more bandwidth than NBC at a given time, it could be that 44-1 takes 70% (for example) then there's 30% left for 4-1/4-2/44-2. The equipment attempts to balance as best as possible, and on average, that means that 4-1 and 44-1 should have about a 50/50 split as a general matter.

For WUSA, however, they're sharing with WJAL on 68-1. But they're not commonly owned, and they've arranged that WJAL can use exactly 25% of the channel 9 bandwidth. Additionally, during NFL, 9-2 gets turned off, so the full ~14 Mbps goes to 9-1.

There's your difference in size.

- Trip
Thanks Trip. That is great info although disappointing on the NBC side. 50% compression is an accurate term? I always thought CBS had a great picture. How would this compare to FiOS or Comcast typically? I have not yet done a test with the ABC and FOX 720P stations. What can I expect there?
sjm817 is offline  
post #9 of 121 Old 11-13-2018, 09:47 AM
AVS Forum Special Member
 
JHBrandt's Avatar
 
Join Date: Apr 2008
Location: S. Garland, TX
Posts: 6,426
Mentioned: 60 Post(s)
Tagged: 0 Thread(s)
Quoted: 2544 Post(s)
Liked: 1232
One of the advantages of variable bit-rate encoding is that you can often get better video than the bit rate suggests. The bandwidth goes wherever it's most needed at that particular point in time. The bit rate drops off when there's less movement in the picture.

Still, there's only so much you can fit into a 19.39Mb/s stream. What happens if both HD streams happen to need lots of bandwidth at the same time? That's where your PQ drops off....
BiggAW likes this.
JHBrandt is offline  
post #10 of 121 Old 11-14-2018, 05:30 AM
AVS Forum Addicted Member
 
Trip in VA's Avatar
 
Join Date: Jun 2003
Location: Alexandria, VA, US
Posts: 16,200
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 1245 Post(s)
Liked: 420
Send a message via AIM to Trip in VA
Quote:
Originally Posted by sjm817 View Post
Thanks Trip. That is great info although disappointing on the NBC side. 50% compression is an accurate term? I always thought CBS had a great picture. How would this compare to FiOS or Comcast typically? I have not yet done a test with the ABC and FOX 720P stations. What can I expect there?
As JHBrandt indicated, the variable bitrate encoding attempts to balance as best as possible. At no point did I indicate that "50% compression" is an accurate term. FiOS and Comcast typically do not do any better than the OTA broadcast, though that depends on the specifics of each situation.

WTTG is like WRC, but more so. 2x720p and 4x480i, but in this case I suspect that Fox usually gets more bandwidth than any of the other channels since it's the one with the motion. I know WDCA carries one or two sporting events on weekends so that time may be best to make a comparison.

WJLA is more like WUSA in that it only has one HD and most of the bandwidth is dedicated to it.

- Trip

N4MJC

Comments are my own and not that of the FCC (my employer) or anyone else.

RabbitEars

"Ignorance and prejudice and fear walk hand in hand..." - Rush "Witch Hunt"

Trip in VA is online now  
post #11 of 121 Old 11-14-2018, 08:34 AM
Super Moderator
 
DrDon's Avatar
 
Join Date: Mar 2002
Location: Metro Detroit, Tampa Bay
Posts: 16,187
Mentioned: 25 Post(s)
Tagged: 0 Thread(s)
Quoted: 1915 Post(s)
Liked: 3615
Quote:
Originally Posted by sjm817 View Post
I always thought CBS had a great picture. How would this compare to FiOS or Comcast typically? I have not yet done a test with the ABC and FOX 720P stations. What can I expect there?
If you mean the same affiliates' picture quality on Comcast or FiOS vs OTA, that'll depend on what the affiliate sends to them. Generally speaking, it's the same format and bitrate that's being broadcast. While it's certainly possible to send MPVDs a higher bitrate than what's being broadcast, it requires, putting it simply, a whole 'nuther rack of expensive gear with no way to recover the cost.

Walking the fine line between jaw-dropping and a plain ol' yawn.
DrDon is online now  
post #12 of 121 Old 11-14-2018, 03:29 PM
Advanced Member
 
nathill's Avatar
 
Join Date: Mar 2004
Location: Bloomington, IN
Posts: 764
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 198 Post(s)
Liked: 102
Quote:
Originally Posted by JHBrandt View Post
One of the advantages of variable bit-rate encoding is that you can often get better video than the bit rate suggests. The bandwidth goes wherever it's most needed at that particular point in time. The bit rate drops off when there's less movement in the picture.

Still, there's only so much you can fit into a 19.39Mb/s stream. What happens if both HD streams happen to need lots of bandwidth at the same time? That's where your PQ drops off....

Terre Haute's WTHI broadcasts have improved a whole bunch through more dynamic variable bit-rates (at least that's my take on why they're better).
Here's the new set-up. Picture quality used to be atrocious on Fox especially, and I seem to remember that the bit rates didn't vary much. They jump around quite a bit now.

WTHI 1 - 4.5 to 8.2 Mbps - CBS - 1080i
WTHI 2 - 4.4 to 7.9 Mbps - FOX - 720p
WTHI 3 - 4.2 to 7.8 Mbps - CW - 720p
WTHI 4 - 1.2 to 2.1 Mbps - Ion - 480i

I can see a definite picture quality improvement, but considering how lousy the picture quality was, that's sort of faint praise. Even my old eyes can tell it's not as good as it could be. No question to me that cramming this many signals into one channel hurts picture quality considerably, even if improved variable-bit rates make things a lot better than they used to be.

I sometimes get really bad pixelation on hockey games over Comcast/Xfinity, and I wonder if they are caused by what JHBrandt has described above.
nathill is online now  
post #13 of 121 Old 11-15-2018, 09:41 PM
AVS Forum Club Gold
 
mrvideo's Avatar
 
Join Date: Jun 2003
Location: Madison, WI
Posts: 7,889
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 1020 Post(s)
Liked: 707
DrDon put me on to this thread, because I have gear to see the CBS and NBC network feeds to the affiliates.

At the outset, let say that what the networks send to the affiliates is above the defacto 2:1 re-coding ratio. The exception is Fox, which sends out a ATSC MPEG-2 encoding that is meant for direct transfer to the transmitter, with space left over for a single SD stream. But, with all these stations doing sharing and/or added SD streams, who knows how damaged the video is before the Fox video is sent to the transmitter. Also, there is remote master control operations. For my local Fox affiliate, Sinclair controls the station out of Milwaukee.

For CBS/CW, the bitrate is ~15 Mbps H.264 4:2:2 CBR.

NBC avg bitrage is 15 Mbps H.264 4:2:0 VBR. As I type this, The E/C mux is black, so it is at the 15 Mbps rate. The M/W mux has black W and active M. The M bitrate is 24 Mbps. When M and W are both active, they run in the 22-24 Mbps range.

Many PBS affiliates downrez the net feed from 1080i to 720p, including my local PBS affiliate. :-( The PBS network feed is ~12.45 Mbps H.264 4:2:0, AC3 audio that switches between 2.0 and 5.1, depending on the source. PBS Kids is ~8 Mbps. Several years ago, PBS was supposed to change over to push technology, i.e., they send the non-live programs to the affiliates ahead of time, so the bitrate of those files should be a lot better than the sat feed. They password protected the engineering website, so I never found out if it was really implemented.

So, if you want the best picture, then put up a 12' BUD and get the network feeds that way. That is except Fox, which still encrypts their feeds.

The net result of all this is that your local affiliates are destroying the video that they get from their networks.

"You're Sherlock Holmes, wear the damn hat!" - Watson to Sherlock
Sherlock - The Abominable Bride - 1/01/16
My 2017 Total Solar Eclipse Photos
mrvideo is offline  
post #14 of 121 Old 11-15-2018, 10:55 PM - Thread Starter
AVS Forum Special Member
 
sjm817's Avatar
 
Join Date: Apr 2007
Posts: 1,145
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 581 Post(s)
Liked: 227
Thanks to all the experts chiming in on this. This has been great info. Continuing on the NFL theme, Fox carries the Thursday game. This is in 720P and I pot the numbers in the first post. Nothing unexpected except the audio. CBS and NBC were 384K. Fox is 448K. ABC doesnt carry NFL so maybe I'll record a College game on Saturday to compare.
sjm817 is offline  
post #15 of 121 Old 11-16-2018, 01:00 AM
AVS Forum Club Gold
 
mrvideo's Avatar
 
Join Date: Jun 2003
Location: Madison, WI
Posts: 7,889
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 1020 Post(s)
Liked: 707
Quote:
Originally Posted by sjm817 View Post
Thanks to all the experts chiming in on this. This has been great info. Continuing on the NFL theme, Fox carries the Thursday game. This is in 720P and I pot the numbers in the first post. Nothing unexpected except the audio. CBS and NBC were 384K. Fox is 448K. ABC doesnt carry NFL so maybe I'll record a College game on Saturday to compare.
I'm surprised that the local CBS and NBC affiliates were running that low for DD5.1 audio. Goes to show that they are trying to squeeze out as much as possible from the ATSC signal.

FYI, CBS/CW use Dolby-E for their audio. ABC and NBC use three MPEG-2 stereo streams to carry their DD5.1 audio. IIRC, 448k is the max for ATSC audio. 640k would have been best, but with the bit robbing that goes on, I doubt that anyone would have gone that high.

Unfortunately, PBS uses 448k for their network feeds.

"You're Sherlock Holmes, wear the damn hat!" - Watson to Sherlock
Sherlock - The Abominable Bride - 1/01/16
My 2017 Total Solar Eclipse Photos
mrvideo is offline  
post #16 of 121 Old 11-17-2018, 01:59 PM - Thread Starter
AVS Forum Special Member
 
sjm817's Avatar
 
Join Date: Apr 2007
Posts: 1,145
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 581 Post(s)
Liked: 227
Added in ABC. Interesting that the 720P ABC has a higher video bitrate than NBC 1080i.
sjm817 is offline  
post #17 of 121 Old 11-17-2018, 03:46 PM
AVS Forum Special Member
 
sneals2000's Avatar
 
Join Date: May 2003
Location: UK
Posts: 7,849
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 463 Post(s)
Liked: 228
Quote:
Originally Posted by mrvideo View Post
I'm surprised that the local CBS and NBC affiliates were running that low for DD5.1 audio. Goes to show that they are trying to squeeze out as much as possible from the ATSC signal.

FYI, CBS/CW use Dolby-E for their audio. ABC and NBC use three MPEG-2 stereo streams to carry their DD5.1 audio. IIRC, 448k is the max for ATSC audio. 640k would have been best, but with the bit robbing that goes on, I doubt that anyone would have gone that high.

Unfortunately, PBS uses 448k for their network feeds.
SVT, the public broadcaster in Sweden, carried 640k AC3 5.1 in their early HD days in the mid-to-late 00s. They are now 448k.
sneals2000 is offline  
post #18 of 121 Old 11-17-2018, 06:49 PM
AVS Forum Club Gold
 
mrvideo's Avatar
 
Join Date: Jun 2003
Location: Madison, WI
Posts: 7,889
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 1020 Post(s)
Liked: 707
Quote:
Originally Posted by sneals2000 View Post
SVT, the public broadcaster in Sweden, carried 640k AC3 5.1 in their early HD days in the mid-to-late 00s. They are now 448k.
Did they gain anything by doing that?

"You're Sherlock Holmes, wear the damn hat!" - Watson to Sherlock
Sherlock - The Abominable Bride - 1/01/16
My 2017 Total Solar Eclipse Photos
mrvideo is offline  
post #19 of 121 Old 11-17-2018, 11:42 PM
Senior Member
 
agus0103's Avatar
 
Join Date: Oct 2010
Location: Brainerd, MN
Posts: 224
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 20 Post(s)
Liked: 29
Quote:
Originally Posted by mrvideo View Post
Several years ago, PBS was supposed to change over to push technology, i.e., they send the non-live programs to the affiliates ahead of time, so the bitrate of those files should be a lot better than the sat feed. They password protected the engineering website, so I never found out if it was really implemented.

PBS implemented this with version 5 of the interconnection system rolled out in 2005. The files are delivered on IP data streams of a DVB-S carrier. PBS is currently in the process of building out a next generation interconnection that will use fiber and the internet to deliver the files rather than satellite.
agus0103 is offline  
post #20 of 121 Old 11-18-2018, 05:24 AM
AVS Forum Special Member
 
sneals2000's Avatar
 
Join Date: May 2003
Location: UK
Posts: 7,849
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 463 Post(s)
Liked: 228
Quote:
Originally Posted by mrvideo View Post
Did they gain anything by doing that?
SVT did 5.1 in the days of their SD DVB-T 16:9 576i25 broadcasts (from the late 90s/early 00s) but don't know if that was 640k or if the 640k was only for their SVT HD service which launched in around 2006 (and carried SVT1 and SVT2 shows that were in HD when the main services were SD outlets. This was the same approach used by the BBC in the early days of HD in the UK, also launching as a trial service in 2006).

I think they switched to 448k when they closed SVT HD and upgraded SVT1 and SVT2 to both be broadcast in HD.

IMO 384k (which BBC One and Two HD used for 5.1 AC3/DD) doesn't sound as good as SVT1 and SVT2 with 448k HD. The off-air recordings I have of SVT HD in 640k do sound very good though.
sneals2000 is offline  
post #21 of 121 Old 11-18-2018, 07:31 AM
Super Moderator
 
DrDon's Avatar
 
Join Date: Mar 2002
Location: Metro Detroit, Tampa Bay
Posts: 16,187
Mentioned: 25 Post(s)
Tagged: 0 Thread(s)
Quoted: 1915 Post(s)
Liked: 3615
Quote:
Originally Posted by sjm817 View Post
Added in ABC. Interesting that the 720P ABC has a higher video bitrate than NBC 1080i.
I'm not sure why that surprises you given Trip's explanation of the channel-sharing going on in DC.

Plus, it's not ABC vs NBC. You're comparing WJLA and WRC. Best to stick with the call letters of the stations you're comparing for clarity's sake. The main-channel bitrates of network affiliates will vary widely by city.

Walking the fine line between jaw-dropping and a plain ol' yawn.
DrDon is online now  
post #22 of 121 Old 11-18-2018, 08:17 AM - Thread Starter
AVS Forum Special Member
 
sjm817's Avatar
 
Join Date: Apr 2007
Posts: 1,145
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 581 Post(s)
Liked: 227
Quote:
Originally Posted by DrDon View Post
I'm not sure why that surprises you given Trip's explanation of the channel-sharing going on in DC.

Plus, it's not ABC vs NBC. You're comparing WJLA and WRC. Best to stick with the call letters of the stations you're comparing for clarity's sake. The main-channel bitrates of network affiliates will vary widely by city.
Understood. I cant edit thread title but added call letters. Surprising was not the best term. Eye opening maybe better.
sjm817 is offline  
post #23 of 121 Old 11-18-2018, 10:56 AM
AVS Forum Addicted Member
 
Trip in VA's Avatar
 
Join Date: Jun 2003
Location: Alexandria, VA, US
Posts: 16,200
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 1245 Post(s)
Liked: 420
Send a message via AIM to Trip in VA
I'm not sure what your reception conditions are like, but in the rare instance that I choose to watch something on the networks, I usually use the Baltimore affiliates over DC.

WBAL (1xHD/1xSD) looks better than WRC (2xHD/2xSD)
WJZ (1xHD/1xSD) looks better than WUSA (2xHD/1xSD)
WBFF (2xHD/2xSD) looks somewhat better than WTTG (2xHD/4xSD)
WMAR (1xHD/3xSD) looks about the same as WJLA (1xHD/3xSD)
WNUV (1xHD/3xSD) looks better than WDCW (2xHD/4xSD)

The exception to the rule is on PBS, where WETA (1xHD/3xSD) is generally better than WMPT (2xHD/2xSD). Both look pretty bad next to the direct PBS satellite feeds, of course, but my dish has been out of commission for... I guess years now. Need to fix that.

- Trip

N4MJC

Comments are my own and not that of the FCC (my employer) or anyone else.

RabbitEars

"Ignorance and prejudice and fear walk hand in hand..." - Rush "Witch Hunt"

Trip in VA is online now  
post #24 of 121 Old 11-18-2018, 12:20 PM - Thread Starter
AVS Forum Special Member
 
sjm817's Avatar
 
Join Date: Apr 2007
Posts: 1,145
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 581 Post(s)
Liked: 227
Quote:
Originally Posted by Trip in VA View Post
I'm not sure what your reception conditions are like, but in the rare instance that I choose to watch something on the networks, I usually use the Baltimore affiliates over DC.

WBAL (1xHD/1xSD) looks better than WRC (2xHD/2xSD)
WJZ (1xHD/1xSD) looks better than WUSA (2xHD/1xSD)
WBFF (2xHD/2xSD) looks somewhat better than WTTG (2xHD/4xSD)
WMAR (1xHD/3xSD) looks about the same as WJLA (1xHD/3xSD)
WNUV (1xHD/3xSD) looks better than WDCW (2xHD/4xSD)

The exception to the rule is on PBS, where WETA (1xHD/3xSD) is generally better than WMPT (2xHD/2xSD). Both look pretty bad next to the direct PBS satellite feeds, of course, but my dish has been out of commission for... I guess years now. Need to fix that.

- Trip
I have an outdoor antenna that is mounted to garage side of house where a DTV dish originally was and cabling already present. It is pointed to the DC towers. I get great reception. Baltimore would need an antenna mounted to opposite side of house ot on roof and new cable run. A lot of work. I can live with what I have.
sjm817 is offline  
post #25 of 121 Old 11-18-2018, 01:11 PM
AVS Forum Club Gold
 
mrvideo's Avatar
 
Join Date: Jun 2003
Location: Madison, WI
Posts: 7,889
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 1020 Post(s)
Liked: 707
Quote:
Originally Posted by agus0103 View Post
The files are delivered on IP data streams of a DVB-S carrier.
Do you happen to have any coordinates of said feed?

"You're Sherlock Holmes, wear the damn hat!" - Watson to Sherlock
Sherlock - The Abominable Bride - 1/01/16
My 2017 Total Solar Eclipse Photos
mrvideo is offline  
post #26 of 121 Old 11-18-2018, 01:18 PM
Senior Member
 
Join Date: Sep 2017
Posts: 206
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 138 Post(s)
Liked: 36
Thumbs up Diginets are where its at!

Quote:
Originally Posted by sjm817 View Post
Oh yeah. Sub-Channels. All those SD channels that I hide/uncheck the boxes for after I do a channel scan!
Oh yeah, those annoying main channels, ABC, CBS, NBC, Fox, CW, all hidden! (Yes I am serious.)

Along with all the foreign, religion, shopping junk...
merman9393 likes this.

Notice: I no longer provide assistance in re OTA antenna and RF related queries.
TampBayOTA is offline  
post #27 of 121 Old 11-18-2018, 08:04 PM
AVS Forum Club Gold
 
mrvideo's Avatar
 
Join Date: Jun 2003
Location: Madison, WI
Posts: 7,889
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 1020 Post(s)
Liked: 707
Quote:
Originally Posted by sneals2000 View Post
IMO 384k (which BBC One and Two HD used for 5.1 AC3/DD) doesn't sound as good as SVT1 and SVT2 with 448k HD.
The sat feeds are that low for AC3? Wow. I do not know what the AAC bitrate is for BBC One and Two, since MediaInfo says that it is variable. I convert the AAC to AC3, as my amp seems to like it better.

"You're Sherlock Holmes, wear the damn hat!" - Watson to Sherlock
Sherlock - The Abominable Bride - 1/01/16
My 2017 Total Solar Eclipse Photos
mrvideo is offline  
post #28 of 121 Old 11-19-2018, 04:05 PM
AVS Forum Special Member
 
sneals2000's Avatar
 
Join Date: May 2003
Location: UK
Posts: 7,849
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 463 Post(s)
Liked: 228
Quote:
Originally Posted by mrvideo View Post
The sat feeds are that low for AC3?
Those are the domestic direct-to-home DVB-S2 broadcasts from the BBC (in the UK the main terrestrial services generally handle their own satellite uplinks on the main satellite platform - which is common to both Sky and Freesat). There are no distribution feeds for internal use by the BBC on satellite (though there is a 'satellite backup' service that allows TV transmitters to be fed should the dual-fibre distribution fail). HD content within the BBC is carried over uncompressed fibre/IP circuits between BBC buildings these days (part of BT's Hermes network)

AIUI DVB-S2 BBC One HD/Two HD/Four HD AC3 2.0 is 192kbps and 5.1 is 384kbps.

Quote:
Wow. I do not know what the AAC bitrate is for BBC One and Two, since MediaInfo says that it is variable. I convert the AAC to AC3, as my amp seems to like it better.
http://www.digitalbitrate.com/dtv.ph...&mux=BBCB-PSB3

Suggests that AAC 2.0 is 128kbps and 5.1 is 320kbps for DVB-T2 BBC One HD, BBC Two HD and BBC Four HD. AAC is a more modern codec than AC3 so should do better. (The UK went for AAC on terrestrial as Dolby didn't have a receiver-mix audio description standard when the UK HD OTA standard was formalised)

Last edited by sneals2000; 11-19-2018 at 04:09 PM.
sneals2000 is offline  
post #29 of 121 Old 11-19-2018, 07:42 PM
AVS Forum Club Gold
 
mrvideo's Avatar
 
Join Date: Jun 2003
Location: Madison, WI
Posts: 7,889
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 1020 Post(s)
Liked: 707
^^^ Thanks for the updates.

I just looked at the chart you linked to and it indicates that the AAC audio is encrypted. Huh?

"You're Sherlock Holmes, wear the damn hat!" - Watson to Sherlock
Sherlock - The Abominable Bride - 1/01/16
My 2017 Total Solar Eclipse Photos

Last edited by mrvideo; 11-19-2018 at 07:45 PM.
mrvideo is offline  
post #30 of 121 Old 11-21-2018, 09:54 PM
AVS Forum Special Member
 
tenthplanet's Avatar
 
Join Date: Feb 2006
Location: North of Mexico, South of Oregon, West of desert
Posts: 4,992
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 1712 Post(s)
Liked: 2141
Quote:
Originally Posted by mrvideo View Post
DrDon put me on to this thread, because I have gear to see the CBS and NBC network feeds to the affiliates.

At the outset, let say that what the networks send to the affiliates is above the defacto 2:1 re-coding ratio. The exception is Fox, which sends out a ATSC MPEG-2 encoding that is meant for direct transfer to the transmitter, with space left over for a single SD stream. But, with all these stations doing sharing and/or added SD streams, who knows how damaged the video is before the Fox video is sent to the transmitter. Also, there is remote master control operations. For my local Fox affiliate, Sinclair controls the station out of Milwaukee.

For CBS/CW, the bitrate is ~15 Mbps H.264 4:2:2 CBR.

NBC avg bitrage is 15 Mbps H.264 4:2:0 VBR. As I type this, The E/C mux is black, so it is at the 15 Mbps rate. The M/W mux has black W and active M. The M bitrate is 24 Mbps. When M and W are both active, they run in the 22-24 Mbps range.

Many PBS affiliates downrez the net feed from 1080i to 720p, including my local PBS affiliate. :-( The PBS network feed is ~12.45 Mbps H.264 4:2:0, AC3 audio that switches between 2.0 and 5.1, depending on the source. PBS Kids is ~8 Mbps. Several years ago, PBS was supposed to change over to push technology, i.e., they send the non-live programs to the affiliates ahead of time, so the bitrate of those files should be a lot better than the sat feed. They password protected the engineering website, so I never found out if it was really implemented.

So, if you want the best picture, then put up a 12' BUD and get the network feeds that way. That is except Fox, which still encrypts their feeds.

The net result of all this is that your local affiliates are destroying the video that they get from their networks.
That's just the beginning. In an attempt to be cinematic there is a ton of shows that are shot soft, and sometimes dark. If you think live sports and the commercials look the best sometimes you're not imagining it. Add that in to everything else and you can see why 4k broadcasting (if it really comes) might not get people all that excited.
JHBrandt likes this.

"Espresso is like tequila, when in doubt apply more shots."
tenthplanet is offline  
Sponsored Links
Advertisement
 
Reply HDTV Technical



Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off