webrtc frame rate and size;

https://webrtchac

om/video-constraints-2/

https://webrtchacks.com/how-to-figure-out-webrtc-camera-resolutions/

6 down vote

Try maxWidth/maxHeight constraints: var video_constraints = { mandatory: { maxHeight: 480, maxWidth: 640 }, optional: [] }; navigator.getUserMedia({ audio: false, video: video_constraints }, onsuccess); Updated (Sep 26, 2013): According to this page; you can set following resolutions (min/max width/height): 1920:1080 1280:720 960:720 640:360 640:480 320:240 320:180 Or Maybe: 1280:800 1280:720 960:600 960:540 640:400 640:360 640:480 480:300 480:270 480:360 320:200 320:180 320:240 240:150 240:135 240:180 160:100 160:90 160:120

分辨率最高的是WVGA:800×480
VGA为标准分辨率:640×480
WVGA 分辨率：800×480

WQVGA 分辨率：480×320
QVGA分辨率：320×240
D1 分辨率：720×576
CIF 分辨率: 352×288
QCIF 分辨率:176×144

Openwebrtc:

QCIF and QVGA are unusable and result in an oddly shaped black frame on the receiving end in Chrome.

CIF works and reduces the latency to 0.5 s or so initially, however latency gradually increases to several seconds and longer.

getUserMedia() constraints

As covered in the What happens when there’s missing media sources? post, getUserMedia() takes a constraints object. The object, as defined in the getUserMedia()W3C specification looks like this:

{ mandatory: { width: { min: 640 }, height: { min: 480 } }, optional: [ { width: 650 }, { width: { min: 650 }}, { frameRate: 60 }, { width: { max: 800 }}, { facingMode: "user" } ] }

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{    mandatory : {      width : { min : 640 } ,      height : { min : 480 }    } ,    optional : [      { width : 650 } ,      { width : { min : 650 } } ,      { frameRate : 60 } ,      { width : { max : 800 } } ,      { facingMode : "user" }    ] }

The spec allows mandatory and optional constraints for both minimum and maximums on:

Object	What it does	Value options
Height	Specifies the video source height	Min and Max of an integer
Width	Specifies the video source width	Min and Max of an integer
FrameRate	specify how many frames to send per second (usually 60 for HD, 30 for SD)	Min and Max of an integer
aspectRatio	height divided by width – usually 4/3 (1.33333333333) or 16/9 (1.7777777778)	Min and Max of an decimal
facingMode	Select the front/user facing camera or the rear/environment facing camera if available	Which camera to choose – currently user, environment, left, or right

In addition to turning audio and video on/off all together, in practice minHeight, minWidth, maxHeight, and maxWidth variables are the most widely supported:

{ "audio": true, "video": { "mandatory": { "minWidth": 320, "maxWidth": 1280, "minHeight": 180, "maxHeight": 720, "minFrameRate": 30 }, "optional": [] } }

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{ "audio" : true , "video" : {    "mandatory" : {    "minWidth" : 320 ,    "maxWidth" : 1280 ,    "minHeight" : 180 ,    "maxHeight" : 720 ,    "minFrameRate" : 30    } ,    "optional" : [ ] } }

I have also seen reference to others that could theoretically be passed down to the libjingle media engine that powers WebRTC. These are out of scope for my camera resolution project, so I did not experiment with them.