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marginal record quality off the air

536 Views 8 Replies 3 Participants Last post by Church AV Guy, Feb 17, 2014

Church AV Guy

Discussion Starter · Feb 14, 2014

During the last month, the LA PBS station has shown the season three episodes of Sherlock. As in the past, I recorded them for my archives. This time however, I was quite surprised at the extreme poor quality of the recording. For example, and this isn't the only one, just the worst one, in episode two (The Sign of Three) there was a scene early on where some flower petals were tossed into the air at Watson's wedding. During that scene, the picture pixelated and broke up so badly it was marginally above the quality of video noise. I went back and looked at the DirecTV high definition feed, and it was as bad as the SD DVD I had made. I sent off to the UK for the Blu-Ray disks (they weren't available in the US yet) and when they arrived, I immediately went to that scene. It was like a totally different show The picture was crisp and showed none of the video artifacts that were in the broadcast. The PBS broadcast was high definition, and the Blu-Ray jacket listed the contents as 1080i, so it was, at least on paper, the same format.

Here is my question: is this a matter of the LA PBS station allocating too much bandwidth to the sub channels leaving too little for the main HD channel, OR, is it a matter of the DirecTV compression getting to me? I want to do an experiment where I record on my trusty EH55 the Blu-Ray output just to see what it looks like. My guess is, it will be far superior to the one I got from DirecTV. (The Blu-Ray player is stacked and rather inaccessible, so getting to it to rewire the output is not easy.) I rarely see this happen, so I was quite surprised that in this case it was so very obvious. My wife, who is a bit of a flower nut, was closely examining the flowers at the wedding, and even she noticed that during that scene, the picture just disintegrated. Needless to say, she LOVED the Blu-Ray version of that scene.

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jjeff

· #2 · Feb 14, 2014

I can't tell from your post but did you actually record it OTA from the LA station or just record it from your DirecTV's rebroadcast of the LA station? I really doubt it's DirecTVs fault, from what I've read they are quite close to the OTA signal. My guess is it's just your local station allocating too little bandwidth to it's main HD channel

In my market my ABC channel is like that, shows like DWTS looks like total crap whenever strobes or motion starts, it's really pathetic but I just have to try and ignore it because there is nothing I can do about it, they have many subs along with a large portion of the HDs channel reserved for MDTV

what a waste.

In my market my local PBS channel looks stellar(just two low bandwidth subs) my only real complaint is my ABC channel, my NBC only has 1 wx sub, my FOX just has one sd duplicate sub and so far my CBS has NO! subs, and really looks great.

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jjeff

· #3 · Feb 14, 2014

You didn't mention the call letters of your local PBS channel but a search of Trip's Rabbitears site shows LA's PBS channel KLCS(channel 58) is only 480i SD

and only 2 channel audio. It also has 3 other SD subs. Another PBS channel listed for the LA market is KVCR(channel 24) out of San Bernadono which looks even worse at 720p stereo and also has 3 SD subs. Wow what a pathetic market for good quality PBS HD! One channel is only SD and the other is 720p of a 1080i network and both have many SD subs......

I'm not sure if my link will work or now but it should get you to rabbitears, from there click LA for your market(#2 market) and you should get all 53 of the channels.

Looks like the 720p channel allocates ~8Mbps for it's main while the 480i channel 4.2Mbps. Actually both are OK for their resolution but for comparison my market is 1080i with 12.4Mbps allocated for the HD

http://www.rabbitears.info/market.php

http://www.avsforum.com/t/191672/los-angeles-ca-ota/9300#post_24226729

http://www.avsforum.com/t/191672/los-angeles-ca-ota/9300#post_24302046 very interesting post

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Kelson

· #4 · Feb 14, 2014

Quote:
Originally Posted by Church AV Guy /t/1517726/marginal-record-quality-off-the-air/0_100#post_24355369

Here is my question: is this a matter of the LA PBS station allocating too much bandwidth to the sub channels leaving too little for the main HD channel, OR, is it a matter of the DirecTV compression getting to me?

I like Sherlock also. I recorded the three episodes OTA from Philly PBS just recently with my TiVo and transferred them to my server. They are 1080i with ~14 Mbps bitrates and look, well like HDTV. After trimmming the extraneous PBS advertisements, each 90 min episode is 9GB in size. The artifacts you are seeing are not a function of the source provided for broadcast but more likely an issue with your station out there. Unfortunately, although the video is 1080i, the audio is a miserable 2.0 stereo. The DVD's of previous seasons are all 5.1 audio.

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Church AV Guy

Discussion Starter · #5 · Feb 15, 2014

jjeff,

The recording I made was from the DirecTV feed. I live over 100 miles from LA itself, in the Indian Wells Valley, which is bowl surrounded by mountains. We get no television that isn't from satellite or brought in by repeater. The IWVTV Booster rebroadcasts several LA stations into the valley, but channel 50 isn't one of them.

The "main" PBS station used to be 28, KCET, but they recently split from PBS. They now are a public broadcasting station, but no longer affiliated with the PBS "network". The providers like DirecTV gave bandwidth preference to KCET because they were the primary station. When KCET left PBS the other stations scrambled to cover the network shows, and Mystery! was given to KOCE, channel 50.

http://www.stationindex.com/tv/callsign/KOCE

It was never as good as KCET, so I think it's a combination of their three sub channels, and the DirecTV bandwidth allocation. Thanks for the link. It appears that others think the KOCE broadcasts are pathetic. Back when I was living in Minnesota, Minneapolis channel 2 was PBS and it was always high quality. Of course, things can change.

Kelson, I should be so lucky to get PBS with that kind of bandwidth allocation. For a market as large as LA, there is a real lack of quality, hence the Blu-Ray purchases.

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jjeff

· #6 · Feb 15, 2014

Wow, hard to believe a market as big as LA(#2 TV market) doesn't have a full bandwidth 1080i PBS channel

As you said my market has KTCA(PBS) which while not perfect isn't bad either, we have a great full bandwidth(no sub channel) CBS channel, which is great for me since the majority of programming I watch is on CBS, and a almost full bandwidth NBC channel which again is good since I also watch quite a bit of NBC. I don't watch much FOX, which in my market seems to have good bandwidth but IMO is kind of soft HD and a channel I only occasionally watch(the CW) which has excellent 1080i HD. No my only complaint is ABC which I don't watch a lot, mainly when DWTS is on and a few other shows. I'm finding myself watching more PBS of late, between Downton Abby, Sherlock, Doc Martin, Bletchly Circle and Call the Midwife to name a few. Also watched Death in Paradise but I'm not sure we'll be getting more episodes. Oh almost forgot about Paradise and Mr. Selfredge which it sounds like we'll be getting more of both

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Church AV Guy

Discussion Starter · #7 · Feb 16, 2014

Quote:
I'm finding myself watching more PBS of late, between Downton Abby, Sherlock, Doc Martin, Bletchly Circle and Call the Midwife to name a few. Also watched Death in Paradise but I'm not sure we'll be getting more episodes. Oh almost forgot about Paradise and Mr. Selfredge which it sounds like we'll be getting more of both

Wow! That's a litany of my wife's PBS watching. As an engineer, she really appreciated The Bletchly Circle.

Anyway, I did that test, where I ran the Blu-Ray output to the input of my Panasonic DVD recorder and made an SD recording. While it was certainly no match for the Blu-Ray HD output, it was much, MUCH better than the video quality I was getting from DirecTV, which quite likely matches the video quality it was getting from KOCE. My wife claimed that if you just watched it, and didn't freeze frame any of it, the video quality of my recording was very watchable. If you give the DVD recorder a good input signal, the quality you can get is really excellent. Had I used XP instead of SP quality, I can only guess it would have been even better.

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jjeff

· #8 · Feb 16, 2014

Quote:
Originally Posted by Church AV Guy /t/1517726/marginal-record-quality-off-the-air#post_24364047

Anyway, I did that test, where I ran the Blu-Ray output to the input of my Panasonic DVD recorder and made an SD recording. While it was certainly no match for the Blu-Ray HD output, it was much, MUCH better than the video quality I was getting from DirecTV, which quite likely matches the video quality it was getting from KOCE. My wife claimed that if you just watched it, and didn't freeze frame any of it, the video quality of my recording was very watchable. If you give the DVD recorder a good input signal, the quality you can get is really excellent. Had I used XP instead of SP quality, I can only guess it would have been even better.

I've done quite a few tests recording from BD vs DVD and even though BD can look much better via HDMI to a HDTV, recording the SD output of the player I much prefer DVD. I even have a rare BD player that has S-video output to make it apples to apples but there must be losses downconverting 1080p(BD format) to 480i(DVD format) so unless I know the material is real HD(like Sherlock would be) I really like to get the DVD for my source instead of BD.

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Church AV Guy

Discussion Starter · #9 · Feb 17, 2014

Quote:
I've done quite a few tests recording from BD vs DVD and even though BD can look much better via HDMI to a HDTV, recording the SD output of the player I much prefer DVD. I even have a rare BD player that has S-video output to make it apples to apples but there must be losses downconverting 1080p(BD format) to 480i(DVD format) so unless I know the material is real HD(like Sherlock would be) I really like to get the DVD for my source instead of BD.

With all that, I still would just be happy if I got a better quality feed for the PBS programming.

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