Problem with a new ATSC 1.0 AVC sub-channel

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RonRN18
Posts: 27
Joined: Sun Jan 24, 2016 2:04 pm

Problem with a new ATSC 1.0 AVC sub-channel

Post by RonRN18 »

I am in the Sacramento television market area. One of our television stations, KCRA (Hearst Communications) recently added a new sub-channel. KCRA is normally our NBC affiliate. Not only does Hearst Communications own KCRA but they also own KQCA, which prior to ATSC 3.0, was MyNetwork (My58). KQCA became the area's ATSC 3.0 lighthouse station. Before this, KCRA had only one sub-channel, MeTV on 3.2. After the transition, KCRA added a few more sub-channels, including 58.1 for KQCA's 1.0 signal. They also added 3.3, which became Story Television. Now, last week, I was looking at my channels list and I saw a new sub-channel of 3.4 which HDHomeRun flags as AVC. As it was something new and I was NOT physically at home, I couldn't use the HDHomeRun app for watching it but as I VPN to my home while outside of the home, I was able to open a network stream using VLC. I was able to see that the new channel is QVC. I am hoping that this is JUST an experiment on their part, as I have no interest in actually watching QVC. The picture quality was a very clear 720x480i that looks perfect for its low resolution; there is no blocking artifact seen on many other 480i MPEG2 sub-channels. The big problem is that VLC does not play any audio. I went into the menus of VLC and looked at the CODEC information, where it lists the AC-3 audio as "Stream 0" and the AVC/h.264 video as "Stream 1". There are also several closed-caption streams listed, which the first CC stream seems to work well. I commented about this on the AVS Forums for our local market and other users reported back on their reception too. One says that they have a TiVo that also played no sound but another had a Samsung television that was playing the video and audio fine. When I got home and thought of it, I tried tuning it in with the HDHomeRun app and absolutely nothing happens when I select channel 3.4 to play... no video or audio. Again, just for the fun of it, I transcoded the 30-second transport stream recording with FFMPEG.

Code: Select all

ffmpeg -i QVC.ts -c:a copy QVC.mkv
This ended up keeping the video as is and the audio as is, but FFMPEG changed the AVC/h.264 to "Stream 0" and the AC-3 audio to "Stream 1" when looking at the CODEC information inside VLC. This also played the 30-second clip the way it was supposed to. I noticed that the picture quality on the QVC was better than one of their other sub-channels, MeTV but it was using nearly half the bandwidth as MeTV too. I'm guessing that this is primarily just a test about converting other sub-channels to AVC instead of MPEG-2, but so far, it appears not much is compatible with their chosen transport stream.

I have heard that other stations have been transmitting AVC video on ATSC 1.0 channels, so I'm curious if KCRA is just doing it wrong or what. I have tried to find contact info for engineering there and I've tried sending an email to the station about it, but so far I have not heard anything back.

RonRN18
Posts: 27
Joined: Sun Jan 24, 2016 2:04 pm

Re: Problem with a new ATSC 1.0 AVC sub-channel

Post by RonRN18 »

I just tried something else concerning this AVC sub-channel... I used Plex Media Server to tune the channel. Plex, my guess is through transcoding, was able to plat the audio with the video, although there was a very poor audio sync to the video.

jasonl
Silicondust
Posts: 16107
Joined: Sun Oct 28, 2007 9:23 pm
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Re: Problem with a new ATSC 1.0 AVC sub-channel

Post by jasonl »

Hearst has added shopping channels on a bunch of their stations recently. I don't think it's going anywhere unless it proves unprofitable.

We'd like to get a sample recording of it to investigate. Odds are they've got something set wrong, and we might be able to figure out what. Save a 30 second unfiltered capture of the channel with the following URL then upload the resulting file to a storage site like Dropbox, Google Drive, OneDrive, or iCloud, use the Get link function to generate a link, and send me a private message with that link.

http://hdhomerun.local:5004/auto/ch35?duration=30

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