Streaming tests

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G8LES
Posts: 18
Joined: Wed Jul 23, 2008 11:28 am

Streaming tests

Post by G8LES » Mon Jun 01, 2015 10:49 am

Hello all some interesting results on firstly the BATC streamer, then comparing to YouTube

1. The standard USB external gizmo (I have the Kworld one 2 audio sockets composite and S-Video) is poor in quality and when used in S-Video mode shows significant chroma on the luminance channel, as the coloured areas of the picture demonstrate a dot pattern on screen.
2. Using the above set up in a dual core (fairly old) desktop limits the streaming to 320 by 240 or frame drops start happening with Windows Media Encoder Live and only VP6.
3. Moving over to the HP xw8600 with dual 4 core X5496 CPU the frame size can be increased to the full 720 by 576 with no drops. Cropping the source is advised to fill the screen on the output.
4. The image quality is significantly increased by using the Black Magic design Decklink capture card.
5. The cabling on SVideo is inadequate on a long run using the multicore 75 ohm type where the brading is lapwoven instead of cross weave and significant edge ringing is noticed on a test card. That describes the style of cable used in commercially available long SVideo cables too. Replace with sat TV cable and convert to SVideo plug to connect to source on short small cables.
6. Here is one for you. Using mini DV player into firewire to SVideo converter. Lots of chroma on luminance channel. Open Svideo plug on commercially made lead. Victor Meldrew moment – I don’t believe it! The plug had been assembled 90 degrees out at both ends such that one coax was connected inner and outer to the 4 pin plug bottom pins or ground, and the other coax had the inner connected to the Y channel and the outer connected to the C channel! As you may guess that has been corrected.
7. The bit rate maxes out at 650 Kbits/sec for BATC or the sound goes intermittent above that setting.
8. The faster PC will deal with H264 level 5.1 and stream in good quality which looks great in full screen. The Slower PC won’t do H264 only VP6.
9. Setting the Adobe encoder to 1024 by 576 for widescreen material is ignored by BATC streamer which remains at 4 by 3 (that is probably old news).
10. YouTube can use the same Adobe encoder. You have to log in to your YouTube channel and set up a live stream which has to comply to 360, 480, 640 or 720 height. Once the vertical size is set for the event you are stuck with that unless the event is cancelled and closed and a new one is started. You need a significant set up time to let YouTube think about what you are sending it, firstly going through the preview stage where it checks your stream then to actually streaming which you do in the event control panel.
11. You have to choose your encoder, Wirecast or Adobe Media Encoder Live. Wirecast is significantly more of a live production tool where you can insert clips to play off HDD on a timeline and insert live capture clips too in between the HDD clips. It will also do chroma key. It is $499 so not a cheap option.
12. You can download the set up profile for Adobe Media Encoder (XML file) but when you load it in it will assume NTSC settings on capture which you will manually re-set to PAL.
13. In Adobe Media Encoder I have found you can set to 720p out, H264 level 5.1 and keep the bit rate under our 900Mbit maximum here. However there is a significant drop in quality on YouTube over BATC streamer for the same data rate, (BATC = good bang for bit) where YouTube seems to be demanding a much higher stream bit rate per frame size, and the end result on YouTube at a lower upload bit rate is a picture with little sharpness/detail but good sound. I am unable to test YouTube at higher data rates due to the current ADSL copper wire connection here. Registered my Superfast broadband interest today, nearest cabinet half way up the next road and not seeing BT Openreach working speedily to improve the number of cabinets in the area, probably the same for alot of people. It is a very interesting exercise drawing 7 km circles round telephone exchanges and seeing all the dwellings that lie outside those circles i.e. too far away to get good speeds over copper.

I hope that is of some interest.

Best regards

Mike

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