Techster

HD on old Macs

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Hi forum,

 

is there any chance to get HD content running on an old PPC Mac?

I used the eyeTV DTT Stick for years, worked great. Unfortunately Standards in Germany have moved on, there is only HD over DVB-T (DTT) by now. I'm not bound to DVB-T, DVB-C (Cable) and DVB-S (Satellite) could be an option. I just was wondering which still works and has the best quality picture running on a G4 eMac with MacOS 10.5. Any experts here?

Regards.

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Okay, this is what I found so far: since the eMac has 1280 pixels in horizontal direction it's good enough to use 720p HD content. The best format a G4 mac (1,42 GHz) can do here is H264 via MPlayer. Motion sometimes rocks a little, but other players (tuned VLC, Quicktime) are even worst. CPU usage is at 80 to 100 %. This setup gives evidence, that HD is possible.

Now how do I get a 720p H264 stream out of the german standard DVB-C, -S or -T2 signal and send it to the mac?

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German DVB-T2 HD is H.265-encoded. This is pretty demanding CPU-wise. Forget about it on a more than 10 year old PPC. No way this will work!

DVB-S2: My experience is that with an Intel Core 2 duo 2.0 GHz, this was just working. With a 1.42 GHz single core G4 CPU, it will not work.

Don't know anything about DVB-C, but I do not think that a G4 CPU can do H.264 in 720p at all, no matter what the means of reception is. Maybe you can decode an H.264 stream in 720p resolution on a PPC, but not in realtime.

 

If your experience is a different one: Please tell us what software (Mplayer or MplayerX) in what version you are using. What OS, what file did you decode? 

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Indeed, my experience is different. No assumptions please. As written before, MPlayer works. "MPlayer OSX Version 1.0 rc1" (2006) is the software which handles 720p in realtime. OS is Mac OS X 10.5.8 and the file is "TV Spot- Tempt" from http://www.hd-trailers.net/movie/star-wars-the-last-jedi/ in 720p for example.

My question is how to change an incoming HD stream (DVB-T2: H265 1080p) and send it to the eMac. Over Wifi? What machine could do the job reliably and without everyday care? An older eyeTV product maybe?

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I've learned, that in other countries DVB-T streams in 720p in H264 and even in old MPEG2 standard  (Australia) are available. Did someone make a test with an G4 in that areas in the past? If someone from those countries could provide me a 30 sec piece of an eyeTV recording I would be very thankful. I could check if the eMac CPU is powerful enough, a proof of concept. Just send me a message. 

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Done! I did some testing and found out mpeg2 works best. I created a file using VideoLan Client with

1280x720 px, 25 fps, 48 kHz, MPEG-TS, mpeg2 encoder.

A full movie is as large as 4 to 5 GB, but who cares for file size in 2018 anyway? Playback takes 70% (VLC) to 80% (eyeTV) CPU.  Picture quality is close to original (DVB-T2), you might get better results with high quality source and professional encoding software. However, that's still the best picture I have ever seen on an eMac.

 

So now I'm able to watch every movie I own in maximum monitor resolution on this vintage machine. The only question left is how to convert a live TV stream to mpeg2 in real time. Does some of the eyeTV products do the job? Or a RaspberryPi? Help me!

Edited by Techster

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With exact the same video snippet and a 1.42GHz G4 CPU running 10.5.8, I get massive dropped frames (can be seen in Statistics window in Mplayer). Especially during the explosion part in the video, the CPU can not cope with the load. Audio gets out of sync with the video, which is as well indicated in the statistics. In this 30s snippet, the A/V offset increases to more than 5s on the machine (Mac Mini PPC 1.42 GHz).

On a MDD dual-CPU machine, clocked at 867MHz, with Mac OSX 10.4.11, it gets even worse: The A/V delay increases to more than 8s.

If you do not encounter this sort of performance shortages on your G4 machine: Congratulations! You have a well-tuned machine.

 

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On 13.1.2018 at 8:02 PM, Techster said:

My question is how to change an incoming HD stream (DVB-T2: H265 1080p) and send it to the eMac. ... What machine could do the job reliably and without everyday care? An older eyeTV product maybe?

What you want would be some sort of a transcoder, that is able to receive the source material (DVB-T2 HD receiver), decodes the 1080p25 H.265 material (not possible by means of software decoding only, so you need some sort of hardware acceleration here), scales it to 720p, re-encodes it to MPEG-2 (with the help of hardware support, the last two mentioned steps are not too much of a demand for todays machines) and then sends it over the network to your destination machine. This is quite an impressing workflow, even more if it shall be done "without everyday care."

If you find a tool (be it hardware or software or a combination thereof), that covers all of these demands, please let us know about the setup.

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On 4.2.2018 at 6:53 PM, Schorschinjo said:

Congratulations!

Thanks, but I didn't tune much. Maybe it's because of 2 GB RAM and a 2009 HDD. And it's a test machine only, I have a clean installation of OS X running.

Anyway, I tested VLC over the last days to convert and stream to the eMac from a 2013 MacBook Air. Result: 0.2 fps :-( Problem seems to be the sending machine, receiving 720p MPEG-2 on the same machine sometimes worked (sent from an eMac)! Conversion of the eyeTV live stream also works when saved in an MPEG-2 TS file, needed 130 - 160 % CPU (4 Cores available). Unfortunately I don't have any other machine to play around. Didn't find out what's wrong, WiFi and CPU are not even close to their limitations on both computers. Using VLC was kind of frustrating as it often crashes, e.g. when I tried ending the stream.

Testing is over now. VLC is too unreliable (even for a proof of concept) and I don't know any better movie streaming software. I think, there's only two ways out:

1 RaspberryPi (or similar) with enough CPU power, coming maybe 2019 + reliable software

2 A dream device called "eyeTV legacy box" or something, which does conversion and streaming over WiFi (or USB 2.0). Damn Geniatech, where do I have to wrench you to bring that device?

If anyone has a real life solution please post it here, I'll test it.

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On 4.2.2018 at 6:53 PM, Schorschinjo said:

... I get massive dropped frames (can be seen in Statistics window in Mplayer).

Sorry, forgot: I found Core Player in the mean time. Poor interface, best efficiency (720p H264). Try it out.

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Thanks for the hint with CorePlayer. This is really an astonishing piece of software. Seems far more performant than MPlayer, MPlayer Extended and VLC. The trailer mentioned by you earlier even plays smoothly on a MDD G4 @ 867MHz.

Only QuickTime Player seems to come close. Give this one a try as well!

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