網絡電視、PC-TV互聯

網絡電視、PC-TV互聯

(2013-12-22 22:51:46) 下一個

PC輸出送電視顯示，在PC出現後就開始了，當時的CGA與NTSC模擬電視頻率相近，分辨率 640x200。現在的數碼電視1920x1280居多，可以支持幾種不同分辨率，PC的分辨率反而低些。但兩者都可以微調屏幕尺寸，因此對接隻要選兩者 相近的分辨率，接口一致（通常是HDMI，或將HDMI轉DVI)就可以了。

電視與PC的不同，在於前者功能單一，CPU速度不高需加硬件解碼，固件變動不大支持的標準不多；後者多用Intel/AMD高速CPU軟件解碼，支持較 多的編碼且升級頻繁，用法繁複。介於兩者之間的高清播放器應運而生，支持多種編碼格式，內置硬件解碼（有的內置硬盤或藍光），高清播放機的代表是 roku，蘋果的就是apple TV，google的stick叫Chromecast ，都是為了解碼去電視看。這裏穩定性最好的可能是蘋果（封閉式設計支持的流媒體格式較少），其次是roku，google的stick看來處理能力有限。類似roku的高清播放機國內有幾百種產品，大家都是在3-4個平台上開發的。

HDTV出台十幾年了，ATSC/DVB都是MPEG2，目前流媒體即在網上傳的媒體以H.264（MPEG4 part 10）和Divx（MPEG4)居多，H.265標準也已發布，也會先以PC軟件的方式使用。

網絡電視開始是指用網絡傳輸電視的內容，泛指網上的時事新聞節目但也包括音樂電影等。目前的smart TV帶有網絡接口，瀏覽器的質量比2000年時有很大提高（微軟webTV計劃在2000年左右以失敗告終）。而網絡互連各類設備的一個重要的plug- and-play的標準就是DLNA。網絡媒體要求網速高且穩定，媒體交換機（switch）的要點就是保證媒體傳輸延遲小。交換機可用帶寬不超過標稱 70%，因此交換機/路由器（router）的性能也很重要，目前無線是個趨勢。蘋果喜歡把標準冠以自己的名稱：

AirPort	802.11b	11 Mbps	150 Feet	2.4 GHz
AirPort Extreme	802.11g	54 Mbps	50 Feet	2.4 GHz
AirPort Extreme	802.11a*	54 Mbps	50 Feet	5 GHz
AirPort Extreme	802.11n	300 Mbps 450 Mbps§	175 Feet	2.4/5 GHz

最新802.11ac的帶寬約2-~4倍於802.11n。802.11n以普及有150n，300n，600n，900n幾種,實際速率要看產品說明，比如ASUS 300n/900n的路由器是300/450Mbps。目前最好的產品有：http://reviews.cnet.com/best-wireless-routers/
亦即家用可選ASUS RT-N66U router，電腦沒有802.11n的話用ASUS USB-N10 adapter。

家用的PC-TV互連方案有很多種：
1.AppleTV去TV HDMI，Ipad (mini)的WIFI與Apple TV處於同一局域網中，用蘋果的Air play互連: http://support.apple.com/kb/HT4437?viewlocale=zh_TW&locale=zh_TW
不知能否播放ipad存儲的節目？基本上apple的東西都是付費的。
2.roku和其他網絡機頂盒，以及google Chromecast 與appleTV類似，一頭聯網一頭去電視，互連多是DLNA。用SONY PS3也行，支持DLNA。都隻要一般電視就行了，支持的媒體格式不是電視決定的。
3.smartTV帶WIFI/網口，與PC聯網用DLNA看PC上的節目。當然也如appleTV/roku一樣支持netflex，youtube 等。smart TV如VISIO E241I-A1，據說瀏覽速度比samsung快。支持的媒體格式由smart TV決定。
4. PC上加iTune軟件實現air play，也許air play就是apple版的DLNA？
5. PC上加USB-ATSC增加電視/收音調諧。別的方案都是用internet上的無線電台網台。
看來最簡單的就是買smart TV，共享局域網的資源通過DLNA（windows 7以上直接支持，由電視機的media目錄能顯示訪問PC媒體文件，XP則需加裝第三方軟件。（見本文附錄）
6. PS3的DLNA：任何DLNA設備都可以連，例如電視、PC、手機：https://www.youtube.com/watch?v=dqu7BPqjo4s?  
操控PC的無線鍵盤也有許多種（略）。最後說一下硬盤。硬盤至少有消費級、企業級和視頻盤三種。據說前兩種是按5x8小時設計後者用7x24小時工作設計。但由用戶反饋看企業級的或許還是好一些。硬盤早晚都會壞的，每年2-4%。WD質量是黑/紅/普通盤。

PS3原帶wireless遊戲controller，按其上PS3圖標待背部4燈同亮轉為1燈即匹配好。我用的PowerA自帶USB stick，先開PS3再插入USB並按其上Connect紐，此時USB快閃，再按controller上4燈紐，4燈紐閃爍變為穩定單燈就好了，其4象限代表4個頻道之一，這樣就匹配好了。主要鍵是四光標、X(Enter)和O(quit)。PS3 Bluetooth controller需要用wireless contoller進accesory選register BD再按屏幕提示設置來匹配。
附錄： http://thebitplague.wordpress.com/2012/10/22/play-stream-video-from-pc-to-vizio-tv/

How to play movies from your PC on your Vizio Smart TV

Posted on 10/22/2012 by vaughnteegarden 60 Comments

If you were to thumb through the manual of your new Vizio Smart TV, you might come to the conclusion that you cannot play video files stored on your computer’s hard drive on your TV.  The only mention of playing external media involves plugging in a usb drive, and that is limited to photos and music.

After several searches of the internet, I was becoming convinced it couldn’t be done. I read discussions of potentially making a widget for Plex, a popular media server, but no one had written one yet.  My experiments with a couple of different media servers went nowhere.

What the manual doesn’t tell you, and what I now know,  is that your TV is capable of displaying media streamed from a DLNA-compliant media server. I stumbled across a post here suggesting that if a DLNA media server was present, it would show under the “Media” menu (which was only mentioned in the manual with regards to playing music off a usb drive).

I looked up the wikipedia entry for DLNA media servers, and noticed the PS3 Media Server was listed. I had read a recommendation of this server as being one that “just works”, and so I downloaded and ran it.

PS3 Media Server – Main Screen

Once the server was running, I checked the Media app on the TV, and sure enough my computer was listed. Clicking on the computer name, you have the choice of Photo, Music, or Video… I chose video.

By default it was sharing my entire PC, at the “My Computer” level. That was no good, so on the “Navigation/Share Settings” tab I added my video directory as a shared folder. I pressed Save at the top of the screen, and restarted the server. It now correctly restricted sharing to only the one folder.

PS3 Media Server – Specify Shared Folder

From then on, it “just worked”. Clicking on a video file played the movie almost immediately, and the play, pause, fast forward and rewind buttons on my Vizio remote all worked. Video and Audio quality were both excellent, given the source file.

Some notes about this tip…

• I use Windows XP at home because I’m a cheap bastard, and I don’t see  a point in upgrading until I upgrade my hardware as well.  I understand some or all Windows 7 systems have a media server built in. If you have Windows 7, fire up your computer, and check the Media item in your TV. You may not need PS3 Media Server at all.
• I believe that for a DLNA media server to work, you must have your PC and TV connected through a DLNA compliant router. I have the excellent Asus RT-N66U, and I can’t recommend it enough. It’s worth the money for the speed, range, and extra features.
• As always, your mileage may vary.

I hope this post helps others searching for a way to play video files from their PC on their Vizio TV.

PS3 Media Server homepage

Optoma HD33 其實這個投影機最大的亮點就是不用買進口的發射器和3D眼鏡，國產創維的大家都知道的，相當好用。型號是RD04SA和RD06SA，發射器網址奉上  http://item.taobao.com/item.htm?spm=a230r.1.10.64.AjFeY9&id=18875988291

WIFI smart TV: Philips 32PFL4909/F7 720P $280(Target sale $230), 40PFL4909/F7 1080P $435 802.11g/n
http://www.walmart.com/ip/Philips-32PFL4909-32-720p-LED-LCD-TV-16-9-HDTV/39364375
http://download.p4c.philips.com/files/3/32pfl4908_f7/32pfl4908_f7_pss_aenus.pdf室內天線： RCA 1650R，平躺最好，也可直立。
上述smartTV太厚了準備退掉。薄的1080P有Samsung 5999=1.5",5500=1.9",ViZIO M322i=2.08"，不然Ruko或Chromecast好了。