sdp

问题 According to RFC 6184: Annex B of H.264 defines an encapsulation process to transmit such NALUs over bytestream-oriented networks. In the scope of this memo, Annex B is not relevant. I see a lot of examplex, including in RFC6236, of SPS/PPS like this a=fmtp:99 packetization-mode=0;profile-level-id=42e011; \ sprop-parameter-sets=Z0LgC5ZUCg/I,aM4BrFSAa However, according to H.264, Annex B, there should be no comma, and a preamble must be added to the beginning of both SPS and PPS (and after

问题 I am missing some fundamental thing in translating an UDP stream of a SDP session into a decodable H.264 stream. I am testing with a H.264 capable camera and can play the stream with a player directly. When I try to play the translated stream it will not be recognized by the player (missing header error). However I have to decode the UDP stream to be able to integrate this in a Java application for which there are some decoders around. I have seen very good answers to following questions

问题 I've been googling a way to change codec in Chrome's implementation of WebRTC, but there doesn't seem to be a way. How can I change the default codec used(audio or video) in a WebRTCpeer connection in Chrome? 回答1: Yes, you can change the codec to be anything you want...as long as Chrome supports it. Right now, audio wise, the only supported codecs are PCMA, PCMU, ISAC, and OPUS(the default). For Video you have VP8(also H264 on some systems with FireFox). To use any of these codecs as default,

问题 I've been googling a way to change codec in Chrome's implementation of WebRTC, but there doesn't seem to be a way. How can I change the default codec used(audio or video) in a WebRTCpeer connection in Chrome? 回答1: Yes, you can change the codec to be anything you want...as long as Chrome supports it. Right now, audio wise, the only supported codecs are PCMA, PCMU, ISAC, and OPUS(the default). For Video you have VP8(also H264 on some systems with FireFox). To use any of these codecs as default,

问题 In a SIP video call, the receiver of the video stream respond with the capabilities of its decoder. The parameter which defines that is the profile-level-id . Here is an example value of the profile-level-id parameter: 428014 RFC 6184 defined that as A base16 [7] (hexadecimal) representation of the following three bytes in the sequence parameter set NAL unit is specified in 1: 1) profile_idc, 2) a byte herein referred to as profile-iop, composed of the values of constraint_set0_flag,

问题 What is the meaning of Base64 decoded bytes in sprop-parameter-sets in SDP for a h264 stream? How can I know the video size from this example? SDP example: sprop-parameter-sets=Z0IAKeNQFAe2AtwEBAaQeJEV,aM48gA== First part decoded from Base64 to Base16: 67 42 00 29 E3 50 14 07 B6 02 DC 04 04 06 90 78 91 15 Second part (comma separated): 68 CE 3C 80 ANSWER: Fetching the dimensions of a H264Video stream 回答1: The spec you require is available for free download from the ITU website here:- H.264

问题 What is the meaning of Base64 decoded bytes in sprop-parameter-sets in SDP for a h264 stream? How can I know the video size from this example? SDP example: sprop-parameter-sets=Z0IAKeNQFAe2AtwEBAaQeJEV,aM48gA== First part decoded from Base64 to Base16: 67 42 00 29 E3 50 14 07 B6 02 DC 04 04 06 90 78 91 15 Second part (comma separated): 68 CE 3C 80 ANSWER: Fetching the dimensions of a H264Video stream 回答1: The spec you require is available for free download from the ITU website here:- H.264

问题 I hope there is no flaw in the logic. Step 1: caller creates offer Step 2: caller sets localDescription Step 3: caller sends the description to the callee //------------------------------------------------------// Step 4: callee receives the offer sets remote description Step 5: callee creates answer Step 6: callee sets local description Step 7: callee send the description to caller //------------------------------------------------------// Step 8: caller receives the answer and sets remote

问题 Are IceCandidate and SDP fixed values? Is this a good idea to store them in a server database instead of retrieving on every connection? If updating these data is unavoidable, when should I do it? 回答1: No they are not fixed values. Ice candidates locate the user in the network topology they reside in at present , which unless you have a static IP (which almost nobody has) AND a wired internet connection AND a static LAN address, AND a desktop computer that connects solely through these means

问题 Not sure it is possible, but how can I get a single Image from video stream WITHOUT connecting the stream (rtsp) itself (I have bandwidth issue)? (priority to python but any code framework/language will be good). This is an example SDP file of the stream: v=0 o=Teleste 11501847 688 IN IP4 1.1.1.1 s=unnamed (mpeg4/tx-1) i=Teleste MP-X AUDIO/VIDEO Encoder c=IN IP4 221.1.1.1/64 t=0 0 m=video 4002 RTP/AVP 96 b=AS:6400 a=rtpmap:96 MP4V-ES/90000 a=fmtp:96 profile-level-id=1;config