RF HDTV Modulator for DVHS VCR with built in ATSC tuner - Page 6 - AVS | Home Theater Discussions And Reviews
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post #151 of 163 Old 11-09-2014, 02:50 PM
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Originally Posted by cubsking99 View Post
Are you transcoding the video or just stream copying it?
Transcoding but would prefer copying if possible and then packetize the output.

The open caster manual used ffmpeg to extract stream and then seemed to use x264 (patched) to packetize it. But doing so still took 30% of my CPUs. When I tried all 3 cams, the CPUs were at 100%. Note that this is a virtual machine but still, even on bare bone, I'm sure it'd be sucking a lot of CPU.

So, yeah, my goal is copy if possible and then chunk it up (es -> pes -> ts -> mux -> atsc).

Steph
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post #152 of 163 Old 11-10-2014, 07:17 AM
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Originally Posted by stefvie2k View Post
Transcoding but would prefer copying if possible and then packetize the output.

The open caster manual used ffmpeg to extract stream and then seemed to use x264 (patched) to packetize it. But doing so still took 30% of my CPUs. When I tried all 3 cams, the CPUs were at 100%. Note that this is a virtual machine but still, even on bare bone, I'm sure it'd be sucking a lot of CPU.

So, yeah, my goal is copy if possible and then chunk it up (es -> pes -> ts -> mux -> atsc).

Steph
I don't think you need to re-encode to do it. Try this:

Code:
ffmpeg -re -i SOURCE_URL -c:v copy -c:a copy -f mpegts
udp://127.0.0.1:1234?pkt_size=188&buffer_size=65535
You can use the pkt_size directive on RTP or UDP streams coming from ffmpeg. For more info, see here:

https://www.ffmpeg.org/ffmpeg-protocols.html

Hope that helps!

Mark
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post #153 of 163 Old 11-10-2014, 07:09 PM
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Quote:
Originally Posted by cubsking99 View Post
I don't think you need to re-encode to do it. Try this:

Code:
ffmpeg -re -i SOURCE_URL -c:v copy -c:a copy -f mpegts
udp://127.0.0.1:1234?pkt_size=188&buffer_size=65535
You can use the pkt_size directive on RTP or UDP streams coming from ffmpeg. For more info, see here:

https://www.ffmpeg.org/ffmpeg-protocols.html

Hope that helps!

Mark
Thanks... but I managed to get it to work with no transcoding. Basically, I'm going from my IP CAM's H264/AVC Part 10 stream to mpeg transport stream. Then I extract the video PES out of the TS and re-mux it into my ATSC transport stream with all my other PIDs.

...
ffmpeg -re -rtsp_transport tcp -i "rtsp://admin:12345@cam1.local:554/Streaming/Channels/1" -map 0:0 -an -c:v copy -streamid 0:65 -bsf dump_extra -y input.ts &
ts2pes input.ts 65 > video.pes &
...

... PID 65 is my Video stream defined as H264/AVC (0x1b) so I'm now able to broadcast my IP CAM in 1080P in H264 to my TVs.

Again, once I'm all done with my testing, I'll upload all my scripts to GitHub.

Steph
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post #154 of 163 Old 11-22-2014, 04:57 AM
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So Trip, did you get your stuff working?

JamesMHC, can you check your private messages?
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post #155 of 163 Old 11-22-2014, 07:59 PM
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Yes, I've successfully piped LPB through the house via your software. I was tinkering with my dish again today and have a borderline signal on OETA which means I should be close to having a signal good enough to try sending that one out as well.

I look forward to future developments!

- 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"

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post #156 of 163 Old 11-24-2014, 04:05 PM
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Quote:
Originally Posted by stefvie2k View Post
my Video stream defined as H264/AVC (0x1b) so I'm now able to broadcast my IP CAM in 1080P in H264 to my TVs.
So if you're leaving it H264, are your TVs able to natively show that or do you have something else decoding the stream to display?

I'm looking forward to seeing your scripts and source when you can get them posted...
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post #157 of 163 Old 11-25-2014, 06:31 PM
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Originally Posted by cubsking99 View Post
So if you're leaving it H264, are your TVs able to natively show that or do you have something else decoding the stream to display?

I'm looking forward to seeing your scripts and source when you can get them posted...
Yeah, my Samsung Smart TV (series 6 2013 model) is able to decode the h264 stream, my old Sharp and Samsung TV/Monitor aren't able to.

I'm a bit busy lately because my son is having an asthma flare-up... but hopefully I'll be able to post this up soon...

Here's the ffmpeg/x264 script that I used to generate the test pattern.

Code:
~/bin/ffmpeg -v 0 -re -f lavfi -i "smptehdbars=size=1920x1080:rate=$video_frame_rate" \
  -vf drawtext="fontsize=15:fontfile=/usr/share/fonts/truetype/dejavu/DejaVuSansMono.ttf:timecode='00\:00\:00\:00':rate=$video_frame_rate:text='TCR\:':fontsize=72:fontcolor='white':boxcolor=0x000000AA:box=1:x=940-text_w/2:y=650" -c:v rawvideo -an -f yuv4mpegpipe -y video.y4m &

~/bin/x264 --profile baseline --level 4.0 --nal-hrd cbr --vbv-bufsize 200 --bitrate 720 --keyint 12 --vbv-init 0 -o video.pes video.y4m &
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post #158 of 163 Old 12-05-2014, 08:54 PM
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Hi All,

I've push new version of my program along with the source code onto the GitHub site at https://github.com/stefvie2k/HDTV998Server

PS: If anyone have some spare HDTV998 cards to donate me, let me know. Looks like the eBay seller of the "Lot of 5 HDTV998 cards" took my $ and closed his eBay store (hopefully will get my $ back once the PayPal resolution completes).

Enjoy,

Steph

Last edited by stefvie2k; 12-05-2014 at 10:00 PM.
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post #159 of 163 Old 12-19-2014, 04:57 AM
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Anyone know when the patents run out for the technology to produce a reasonable cost 8VSB modulator?

.
.
Abundant OTA television is what makes this country different from all others. Lets keep it this way. If you like Wi-Fi so much, OTA fits right in. After all, it is wireless.
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post #160 of 163 Old 12-19-2014, 02:54 PM
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Anyone know when the patents run out for the technology to produce a reasonable cost 8VSB modulator?
Some of them have already expired in 2009. But that's not the reason why there are no low-cost modulators. It's more a function of the hardware required to generate the 8VSB signal.

For an NTSC modulator, all you need are a few transistors. For an 8VSB modulator, you need a D/A converter that can do 10.76 Msamples/s, an IQ modulator, an RF oscillator that has low enough phase noise to not destroy the signal and other not so cheap components.

The lowest cost more or less "off the shelf" solution today is $300 with a HackRF SDR board.

https://greatscottgadgets.com/hackrf/

I'm using the bladeRF SDR, which is $420.

http://nuand.com/

Of course, you need a computer to make it go. However, once you've configured everything, you can send any modulation you like. ATSC, QAM, DVB-T, DVB-T2, DVB-S, DVB-S2 and even NTSC.

So if by "reasonable cost", you mean $20 (the price of an NTSC modulator), it's probably never going to happen.

Ron

HD MPEG-2 Test Patterns http://www.w6rz.net
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post #161 of 163 Old 12-20-2014, 05:48 AM
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So if by "reasonable cost", you mean $20 (the price of an NTSC modulator), it's probably never going to happen.
No, I would consdier that 'free'.
More like around $200 (+ or -).

Using those two examples you mentioned, what would be a guess on the cost to complete the package w/o a PC so it would be a stand alone unit?

.
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post #162 of 163 Old 12-20-2014, 06:35 AM
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Quote:
Originally Posted by videobruce View Post
No, I would consdier that 'free'.
More like around $200 (+ or -).

Using those two examples you mentioned, what would be a guess on the cost to complete the package w/o a PC so it would be a stand alone unit?
The two examples quoted are SDR (Software Defined Radios). They require a PC to do the maths required to generate the I/Q signals that are fed over USB to the SDR device - effectively the PC is doing a lot of the processing required to modulate the signal. You will need a reasonably powerful PC to drive them - though this could be a small ITX box rather than an ATX or uATX tower I guess? (Don't think the lower power ARM boxes would have the processing grunt required for ATSC and DVB modulation?)
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post #163 of 163 Old 12-20-2014, 12:30 PM
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On bladeRF, the Nuand folks have moved some of the 8VSB functionality into the on-board FPGA. Instead of sending the raw IQ samples to the card, the 3-bit 8VSB modulation levels are sent. In theory, the entire 8VSB modulator could be moved into the FPGA, but it hasn't been attempted yet.

It takes significantly less CPU, but I haven't experimented with any of the low cost computer modules to see exactly what would work. However, there are some pretty powerful modules available now that make the Raspberry Pi look like a toy. The popular one with the SDR crowd is the Odroid U3.

http://www.hardkernel.com/main/main.php

Assuming that module could deliver enough performance, it gets you in the less than $500 range.

Here are the ATSC flow graphs with the first one doing all the processing on the PC and the second one using the FPGA accelerator. The symbol mapper block in the FPGA flow just packs four 3-bit modulation levels into a 32-bit word that the osmocom sink understands. The WX GUI FFT Sink block in the PC-based flow is optional and just displays the generated ATSC waveform (see last picture).







Ron

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