[SBE] The life of a spot after DG sends it to you...

[Thomas Shanks]

Perhaps it's time for universal algorithms for coding artifact reduction pre-processing to be perfected?  Currently, this effort is being solved in the encoder in an encoding-specific manner.  However, a general coding-load reduction technique might be beneficial if several layers of re-encoding are foreseen, such as with cable company proprietary algorithms on top of ATSC MPEG..  

We all already do this with audio.

Maybe the signal processing types on here or SMPTE could comment?


Thomas Shanks

 
-----Original Message-----
From: sbe-request at sbe.org

Date: Wed, 20 May 2009 22:56:46 
To: <sbe at sbe.org>
Subject: SBE Digest, Vol 176, Issue 2


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SBE Roundtable

Today's Topics:

   1. The life of a spot after DG sends it to you... (Ryan Salazar)
   2. Re: The life of a spot after DG sends it to you... (Crum, Kate)
   3. Re: The life of a spot after DG sends it to you... (Ryan Salazar)
   4. Re: The life of a spot after DG sends it to you... (John Peterson)
   5. Re: The life of a spot after DG sends it to you... (Chris Spacone)
   6. Re: The life of a spot after DG sends it to you... (Ryan Salazar)
   7. Re: The life of a spot after DG sends it to you...
      (Henry M. Seiden)


----------------------------------------------------------------------

Message: 1
Date: Wed, 20 May 2009 15:12:06 -0400
From: "Ryan Salazar" <ryan at ryansalazar.net>
Subject: [SBE] The life of a spot after DG sends it to you...
To: "sbe member discussion mail list" <sbe at sbe.org>
Message-ID: <20090520191206.a4843ae5 at mail.ryansalazar.net>
Content-Type: text/plain;	charset="us-ascii"

Everyone,

I figured this would be the best place for me to ask this question...

We send spots (post production facility), to DG Fast Channel via automation. DG always tells us the spots look great, in fact, better than most spots they receive. They then send the spot to stations via their "Spotbox".

Recently, we had an instance where they sent a spot to CBS-National. CBS then fed the spot live via satellite to a local station. That local station then fed it to the viewers. We received a complaint that the spot was pixelated and blurry. I will admit, our disclaimers were way to small, but we had strange artifacting that we don't normally have an issue with. I also saw a considerable amount of blocks on the screen during fast movement of graphics. I've seen this before after files were converted over and over.

I assume this is because of all the levels the file went through. Us to DG, DG to CBS. Then, CBS via Satellite to the station and the station broadcasts.

Any ideas? I know I can't really control all the points, but want to see what else I can come up with.

Thanks!


------------------------------

Message: 2
Date: Wed, 20 May 2009 15:42:20 -0400
From: "Crum, Kate" <Kcrum at thinktv.org>
Subject: Re: [SBE] The life of a spot after DG sends it to you...
To: "sbe member discussion mail list" <sbe at sbe.org>
Message-ID:
	<50CC087BEE54104BB735761357D590B90D0246 at thinktv3-pbs.internal.gdpt.org>
	
Content-Type: text/plain;	charset="iso-8859-1"


Where in the chain were you receiving the complaints? (CBS, affiliate, viewers?) Sometimes we have issues with our local cable companies resulting from their compression of our signal. That may or may not be another factor to consider, depending on where the problem is showing up.

Good Luck!
Kate

-----Original Message-----
From: sbe-bounces at sbe.org [mailto:sbe-bounces at sbe.org]On Behalf Of Ryan
Salazar
Sent: Wednesday, May 20, 2009 3:12 PM
To: sbe member discussion mail list
Subject: [SBE] The life of a spot after DG sends it to you...


Everyone,

I figured this would be the best place for me to ask this question...

We send spots (post production facility), to DG Fast Channel via automation. DG always tells us the spots look great, in fact, better than most spots they receive. They then send the spot to stations via their "Spotbox".

Recently, we had an instance where they sent a spot to CBS-National. CBS then fed the spot live via satellite to a local station. That local station then fed it to the viewers. We received a complaint that the spot was pixelated and blurry. I will admit, our disclaimers were way to small, but we had strange artifacting that we don't normally have an issue with. I also saw a considerable amount of blocks on the screen during fast movement of graphics. I've seen this before after files were converted over and over.

I assume this is because of all the levels the file went through. Us to DG, DG to CBS. Then, CBS via Satellite to the station and the station broadcasts.

Any ideas? I know I can't really control all the points, but want to see what else I can come up with.

Thanks!
_______________________________________________
The SBE Roundtable, SBE at sbe.org
To unsubscribe, go to http://seven.pairlist.net/mailman/options/sbe

http://seven.pairlist.net/mailman/listinfo/sbe




------------------------------

Message: 3
Date: Wed, 20 May 2009 18:56:17 -0400
From: "Ryan Salazar" <ryan at ryansalazar.net>
Subject: Re: [SBE] The life of a spot after DG sends it to you...
To: "'sbe member discussion mail list'" <sbe at sbe.org>
Message-ID: <3179e9d0-ff37-4866-acb3-8c703d9317c6 at ryansalazar.net>
Content-Type: text/plain;	charset="iso-8859-1"

Hello,

The complaint came from a client that was viewing the spot locally. Never thought about the cable tv company being in the middle. The other spots before our spot didn't look so hot either, but ours was really bad.

Ryan

-----Original Message-----
From: sbe-bounces at sbe.org [mailto:sbe-bounces at sbe.org] On Behalf Of Crum, Kate
Sent: Wednesday, May 20, 2009 3:42 PM
To: sbe member discussion mail list
Subject: Re: [SBE] The life of a spot after DG sends it to you...


Where in the chain were you receiving the complaints? (CBS, affiliate, viewers?) Sometimes we have issues with our local cable companies resulting from their compression of our signal. That may or may not be another factor to consider, depending on where the problem is showing up.

Good Luck!
Kate

-----Original Message-----
From: sbe-bounces at sbe.org [mailto:sbe-bounces at sbe.org]On Behalf Of Ryan
Salazar
Sent: Wednesday, May 20, 2009 3:12 PM
To: sbe member discussion mail list
Subject: [SBE] The life of a spot after DG sends it to you...


Everyone,

I figured this would be the best place for me to ask this question...

We send spots (post production facility), to DG Fast Channel via automation. DG always tells us the spots look great, in fact, better than most spots they receive. They then send the spot to stations via their "Spotbox".

Recently, we had an instance where they sent a spot to CBS-National. CBS then fed the spot live via satellite to a local station. That local station then fed it to the viewers. We received a complaint that the spot was pixelated and blurry. I will admit, our disclaimers were way to small, but we had strange artifacting that we don't normally have an issue with. I also saw a considerable amount of blocks on the screen during fast movement of graphics. I've seen this before after files were converted over and over.

I assume this is because of all the levels the file went through. Us to DG, DG to CBS. Then, CBS via Satellite to the station and the station broadcasts.

Any ideas? I know I can't really control all the points, but want to see what else I can come up with.

Thanks!
_______________________________________________
The SBE Roundtable, SBE at sbe.org
To unsubscribe, go to http://seven.pairlist.net/mailman/options/sbe

http://seven.pairlist.net/mailman/listinfo/sbe


_______________________________________________
The SBE Roundtable, SBE at sbe.org
To unsubscribe, go to http://seven.pairlist.net/mailman/options/sbe

http://seven.pairlist.net/mailman/listinfo/sbe



------------------------------

Message: 4
Date: Wed, 20 May 2009 18:17:08 -0500
From: John Peterson <jpeterson at prairiepublic.org>
Subject: Re: [SBE] The life of a spot after DG sends it to you...
To: sbe member discussion mail list <sbe at sbe.org>
Message-ID:
	<a65bd2330905201617xb8b4181k5456807f7dcf220e at mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"

Ryan brings up an important subject, special with HD productions. Most
distribution methods use some form of digital compression. Multiple
encode/decodes can leave the original product looking soft and washout. One
bad or heavily compression link will give that blocking look.

Producers need to be careful about using too much high chroma motion, lots
of fast cuts or noisey video (old film look might be popular but it is hard
on MPEG encoders). Also with HD, upconverted SD segments might look ok on
the master tape but the added noise in the segment will not look good when
the piece is encoded at 10-18 Mbps for ATSC, HD Satellite or Cable.

John




On Wed, May 20, 2009 at 5:56 PM, Ryan Salazar <ryan at ryansalazar.net> wrote:


> Hello,

>

> The complaint came from a client that was viewing the spot locally. Never

> thought about the cable tv company being in the middle. The other spots

> before our spot didn't look so hot either, but ours was really bad.

>

> Ryan

>

> -----Original Message-----

> From: sbe-bounces at sbe.org [mailto:sbe-bounces at sbe.org] On Behalf Of Crum,

> Kate

> Sent: Wednesday, May 20, 2009 3:42 PM

> To: sbe member discussion mail list

> Subject: Re: [SBE] The life of a spot after DG sends it to you...

>

>

> Where in the chain were you receiving the complaints? (CBS, affiliate,

> viewers?) Sometimes we have issues with our local cable companies resulting

> from their compression of our signal. That may or may not be another factor

> to consider, depending on where the problem is showing up.

>

> Good Luck!

> Kate

>

> -----Original Message-----

> From: sbe-bounces at sbe.org [mailto:sbe-bounces at sbe.org]On Behalf Of Ryan

> Salazar

> Sent: Wednesday, May 20, 2009 3:12 PM

> To: sbe member discussion mail list

> Subject: [SBE] The life of a spot after DG sends it to you...

>

>

> Everyone,

>

> I figured this would be the best place for me to ask this question...

>

> We send spots (post production facility), to DG Fast Channel via

> automation. DG always tells us the spots look great, in fact, better than

> most spots they receive. They then send the spot to stations via their

> "Spotbox".

>

> Recently, we had an instance where they sent a spot to CBS-National. CBS

> then fed the spot live via satellite to a local station. That local station

> then fed it to the viewers. We received a complaint that the spot was

> pixelated and blurry. I will admit, our disclaimers were way to small, but

> we had strange artifacting that we don't normally have an issue with. I also

> saw a considerable amount of blocks on the screen during fast movement of

> graphics. I've seen this before after files were converted over and over.

>

> I assume this is because of all the levels the file went through. Us to DG,

> DG to CBS. Then, CBS via Satellite to the station and the station

> broadcasts.

>

> Any ideas? I know I can't really control all the points, but want to see

> what else I can come up with.

>

> Thanks!

> _______________________________________________

> The SBE Roundtable, SBE at sbe.org

> To unsubscribe, go to http://seven.pairlist.net/mailman/options/sbe

>

> http://seven.pairlist.net/mailman/listinfo/sbe

>

>

> _______________________________________________

> The SBE Roundtable, SBE at sbe.org

> To unsubscribe, go to http://seven.pairlist.net/mailman/options/sbe

>

> http://seven.pairlist.net/mailman/listinfo/sbe

>

> _______________________________________________

> The SBE Roundtable, SBE at sbe.org

> To unsubscribe, go to http://seven.pairlist.net/mailman/options/sbe

>

> http://seven.pairlist.net/mailman/listinfo/sbe

>

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------------------------------

Message: 5
Date: Wed, 20 May 2009 17:41:04 -0700
From: "Chris Spacone" <cspacone at socal.rr.com>
Subject: Re: [SBE] The life of a spot after DG sends it to you...
To: "'sbe member discussion mail list'" <sbe at sbe.org>
Message-ID: <001201c9d9ac$d2c2bdb0$78483910$@rr.com>
Content-Type: text/plain;	charset="us-ascii"

CBS may have pulled the spot from the SpotBox (it is just a Windows box) and
transcoded (perhaps using something like FlipFactory) it to the file format
used on by their video server. Poorly configured FF, low bitrates and a host
of other problems could account for the artifacts. Consider that the local
station that actually played the spot OTA may well have done something
similar to the spot.

As the source material undergoes multiple ingest / encodes / transcode
operations something called concatenation errors begin to creep in.
Essentially the quantization step reduces the 'dynamic range' (for lack of a
better way to describe it) of the video signal which can result in blocky
artifacts. These become more and more pronounced as the material undergoes
multiple passes. Quantization problems are clearly seen with the very low
bitrate video delivered by satellite services. If you watch a black field
you can see 'rings' or contours where the black jumps from one value to
another instead of being smoothly continuous. Another error introduced is
motion artifacting. As each frame of video is analyzed by the encoder a
series of decisions are made that determine how much of the picture can be
thrown away and how much should be kept. Motion vectors from frame to frame
are calculated and a series of MPEG I, P and B frames are generated as part
of a GOP (Group Of Pictures).

These artifacts can become quite obvious when the material has lots of very
small type / detail. If you can pause the playback and check  the edges of
vertical and horizontal elements you will see a sort of 'noise' (I have
heard it called mosquito noise). This noise is directly related to the
amount of quantization being applied to the video.

But all of this is speculation and partly lecture; unless you know the
precise chain the material took along each of the steps you are stuck
guessing. It is possible to 'objectively' measure the end result against the
source material and quantify the underlying impairments by using PQA
testing. Again, all this helps to do is objectively determine if there is a
problem, not precisely where it was introduced (or worse yet how to fix it).

Chris Spacone



-----Original Message-----
From: sbe-bounces at sbe.org [mailto:sbe-bounces at sbe.org] On Behalf Of Ryan
Salazar
Sent: Wednesday, May 20, 2009 12:12 PM
To: sbe member discussion mail list
Subject: [SBE] The life of a spot after DG sends it to you...

Everyone,

I figured this would be the best place for me to ask this question...

We send spots (post production facility), to DG Fast Channel via automation.
DG always tells us the spots look great, in fact, better than most spots
they receive. They then send the spot to stations via their "Spotbox".

Recently, we had an instance where they sent a spot to CBS-National. CBS
then fed the spot live via satellite to a local station. That local station
then fed it to the viewers. We received a complaint that the spot was
pixelated and blurry. I will admit, our disclaimers were way to small, but
we had strange artifacting that we don't normally have an issue with. I also
saw a considerable amount of blocks on the screen during fast movement of
graphics. I've seen this before after files were converted over and over.

I assume this is because of all the levels the file went through. Us to DG,
DG to CBS. Then, CBS via Satellite to the station and the station
broadcasts.

Any ideas? I know I can't really control all the points, but want to see
what else I can come up with.

Thanks!
_______________________________________________
The SBE Roundtable, SBE at sbe.org
To unsubscribe, go to http://seven.pairlist.net/mailman/options/sbe

http://seven.pairlist.net/mailman/listinfo/sbe



------------------------------

Message: 6
Date: Wed, 20 May 2009 22:49:12 -0400
From: "Ryan Salazar" <ryan at ryansalazar.net>
Subject: Re: [SBE] The life of a spot after DG sends it to you...
To: "'sbe member discussion mail list'" <sbe at sbe.org>
Message-ID: <3c4450e8-499b-4d57-976b-70a706191811 at ryansalazar.net>
Content-Type: text/plain;	charset="iso-8859-1"

Thanks for all the comments. I just saw the spot on the air again here in Fort Lauderdale. Not sure how to describe the graphics, but there was a glowing white background around a logo. Right near where the glowing white starts, there's blue text and it's so "washed out". I just saw it on CBS. Not sure if it was a local or national buy, but I think it was national, so probably ran through more passes.

Ryan

-----Original Message-----
From: sbe-bounces at sbe.org [mailto:sbe-bounces at sbe.org] On Behalf Of Chris Spacone
Sent: Wednesday, May 20, 2009 8:41 PM
To: 'sbe member discussion mail list'
Subject: Re: [SBE] The life of a spot after DG sends it to you...

CBS may have pulled the spot from the SpotBox (it is just a Windows box) and
transcoded (perhaps using something like FlipFactory) it to the file format
used on by their video server. Poorly configured FF, low bitrates and a host
of other problems could account for the artifacts. Consider that the local
station that actually played the spot OTA may well have done something
similar to the spot.

As the source material undergoes multiple ingest / encodes / transcode
operations something called concatenation errors begin to creep in.
Essentially the quantization step reduces the 'dynamic range' (for lack of a
better way to describe it) of the video signal which can result in blocky
artifacts. These become more and more pronounced as the material undergoes
multiple passes. Quantization problems are clearly seen with the very low
bitrate video delivered by satellite services. If you watch a black field
you can see 'rings' or contours where the black jumps from one value to
another instead of being smoothly continuous. Another error introduced is
motion artifacting. As each frame of video is analyzed by the encoder a
series of decisions are made that determine how much of the picture can be
thrown away and how much should be kept. Motion vectors from frame to frame
are calculated and a series of MPEG I, P and B frames are generated as part
of a GOP (Group Of Pictures).

These artifacts can become quite obvious when the material has lots of very
small type / detail. If you can pause the playback and check  the edges of
vertical and horizontal elements you will see a sort of 'noise' (I have
heard it called mosquito noise). This noise is directly related to the
amount of quantization being applied to the video.

But all of this is speculation and partly lecture; unless you know the
precise chain the material took along each of the steps you are stuck
guessing. It is possible to 'objectively' measure the end result against the
source material and quantify the underlying impairments by using PQA
testing. Again, all this helps to do is objectively determine if there is a
problem, not precisely where it was introduced (or worse yet how to fix it).

Chris Spacone



-----Original Message-----
From: sbe-bounces at sbe.org [mailto:sbe-bounces at sbe.org] On Behalf Of Ryan
Salazar
Sent: Wednesday, May 20, 2009 12:12 PM
To: sbe member discussion mail list
Subject: [SBE] The life of a spot after DG sends it to you...

Everyone,

I figured this would be the best place for me to ask this question...

We send spots (post production facility), to DG Fast Channel via automation.
DG always tells us the spots look great, in fact, better than most spots
they receive. They then send the spot to stations via their "Spotbox".

Recently, we had an instance where they sent a spot to CBS-National. CBS
then fed the spot live via satellite to a local station. That local station
then fed it to the viewers. We received a complaint that the spot was
pixelated and blurry. I will admit, our disclaimers were way to small, but
we had strange artifacting that we don't normally have an issue with. I also
saw a considerable amount of blocks on the screen during fast movement of
graphics. I've seen this before after files were converted over and over.

I assume this is because of all the levels the file went through. Us to DG,
DG to CBS. Then, CBS via Satellite to the station and the station
broadcasts.

Any ideas? I know I can't really control all the points, but want to see
what else I can come up with.

Thanks!
_______________________________________________
The SBE Roundtable, SBE at sbe.org
To unsubscribe, go to http://seven.pairlist.net/mailman/options/sbe

http://seven.pairlist.net/mailman/listinfo/sbe

_______________________________________________
The SBE Roundtable, SBE at sbe.org
To unsubscribe, go to http://seven.pairlist.net/mailman/options/sbe

http://seven.pairlist.net/mailman/listinfo/sbe



------------------------------

Message: 7
Date: Wed, 20 May 2009 22:37:28 -0400
From: "Henry M. Seiden" <info at techworkspro.com>
Subject: Re: [SBE] The life of a spot after DG sends it to you...
To: sbe member discussion mail list <sbe at sbe.org>
Message-ID: <148F9E0D-B0F0-44F4-B2F2-DED20C5BC652 at techworkspro.com>
Content-Type: text/plain; charset="us-ascii"; Format="flowed";
	DelSp="yes"

As everyone suggested, the path taken decoding and in retransmitting  
as baseband via satellite (as detailed by Ryan, if that's really what  
happened), then re-encoding may have been the final straw causing huge  
potential for artifacts.

Regardless of how it happened, without careful control of the  
distribution of commercial and program content, electronic relay of  
material is not without flaw.

Henry
On May 20, 2009, at 20:41 , Chris Spacone wrote:


> CBS may have pulled the spot from the SpotBox (it is just a Windows  

> box) and

> transcoded (perhaps using something like FlipFactory) it to the file  

> format

> used on by their video server. Poorly configured FF, low bitrates  

> and a host

> of other problems could account for the artifacts. Consider that the  

> local

> station that actually played the spot OTA may well have done something

> similar to the spot.

>

> As the source material undergoes multiple ingest / encodes / transcode

> operations something called concatenation errors begin to creep in.

> Essentially the quantization step reduces the 'dynamic range' (for  

> lack of a

> better way to describe it) of the video signal which can result in  

> blocky

> artifacts. These become more and more pronounced as the material  

> undergoes

> multiple passes. Quantization problems are clearly seen with the  

> very low

> bitrate video delivered by satellite services. If you watch a black  

> field

> you can see 'rings' or contours where the black jumps from one value  

> to

> another instead of being smoothly continuous. Another error  

> introduced is

> motion artifacting. As each frame of video is analyzed by the  

> encoder a

> series of decisions are made that determine how much of the picture  

> can be

> thrown away and how much should be kept. Motion vectors from frame  

> to frame

> are calculated and a series of MPEG I, P and B frames are generated  

> as part

> of a GOP (Group Of Pictures).

>

> These artifacts can become quite obvious when the material has lots  

> of very

> small type / detail. If you can pause the playback and check  the  

> edges of

> vertical and horizontal elements you will see a sort of 'noise' (I  

> have

> heard it called mosquito noise). This noise is directly related to the

> amount of quantization being applied to the video.

>

> But all of this is speculation and partly lecture; unless you know the

> precise chain the material took along each of the steps you are stuck

> guessing. It is possible to 'objectively' measure the end result  

> against the

> source material and quantify the underlying impairments by using PQA

> testing. Again, all this helps to do is objectively determine if  

> there is a

> problem, not precisely where it was introduced (or worse yet how to  

> fix it).

>

> Chris Spacone

>

>

>

> -----Original Message-----

> From: sbe-bounces at sbe.org [mailto:sbe-bounces at sbe.org] On Behalf Of  

> Ryan

> Salazar

> Sent: Wednesday, May 20, 2009 12:12 PM

> To: sbe member discussion mail list

> Subject: [SBE] The life of a spot after DG sends it to you...

>

> Everyone,

>

> I figured this would be the best place for me to ask this question...

>

> We send spots (post production facility), to DG Fast Channel via  

> automation.

> DG always tells us the spots look great, in fact, better than most  

> spots

> they receive. They then send the spot to stations via their "Spotbox".

>

> Recently, we had an instance where they sent a spot to CBS-National.  

> CBS

> then fed the spot live via satellite to a local station. That local  

> station

> then fed it to the viewers. We received a complaint that the spot was

> pixelated and blurry. I will admit, our disclaimers were way to  

> small, but

> we had strange artifacting that we don't normally have an issue  

> with. I also

> saw a considerable amount of blocks on the screen during fast  

> movement of

> graphics. I've seen this before after files were converted over and  

> over.

>

> I assume this is because of all the levels the file went through. Us  

> to DG,

> DG to CBS. Then, CBS via Satellite to the station and the station

> broadcasts.

>

> Any ideas? I know I can't really control all the points, but want to  

> see

> what else I can come up with.

>

> Thanks!

> _______________________________________________

> The SBE Roundtable, SBE at sbe.org

> To unsubscribe, go to http://seven.pairlist.net/mailman/options/sbe

>

> http://seven.pairlist.net/mailman/listinfo/sbe

>

> _______________________________________________

> The SBE Roundtable, SBE at sbe.org

> To unsubscribe, go to http://seven.pairlist.net/mailman/options/sbe

>

> http://seven.pairlist.net/mailman/listinfo/sbe


--

-------------- next part --------------



Techworks Professional Systems, Inc. Henry M. Seiden, Founder
henry<at>techworkspro<dot>com





------------------------------

_______________________________________________
The SBE Roundtable
SBE mailing list
SBE at sbe.org
http://seven.pairlist.net/mailman/listinfo/sbe


End of SBE Digest, Vol 176, Issue 2
***********************************