SDP媒体字段格式
我想创建一个SDP媒体字段及其属性，但有一些我不明白的事情。我浏览并阅读了相关的 RFC 并且我理解了大部分内容每个字段的含义是什么，但我不明白的是如何从 JMF 的音频/视频格式派生，该格式的哪些参数组成了我需要使用的 rtpmap 注册表项。我多次看到
m=audio 12548 RTP/AVP 0 8 101
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=silenceSupp:off - - - -
a=ptime:20
a=sendrecv
从我连接的 pbx 服务器接收到的字段，它们在 JMF 音频格式属性方面的含义是什么。 （我确实知道这些是电信中常用的标准音频格式）
更新：
我更想知道格式参数“0 8 101”最后
m=audio 12548 RTP/AVP 0 8 101
我知道它们是从此列表，但是我如何根据JMF媒体格式确定使用哪一种呢？
提前致谢，
亚当·泽哈维。
I would like to create a SDP media field with its attributes, and there are a few things I don't understand. I've skimmed and read the relevant RFC and I understand most of what each field means, but what I don't understand is how do I derive from the Audio/Video Format of the JMF, which parameters of the format compose the rtpmap registry entries I need to use. I see many times the fields
m=audio 12548 RTP/AVP 0 8 101
a=rtpmap:0 PCMU/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=silenceSupp:off - - - -
a=ptime:20
a=sendrecv
these are received from the pbx server I'm connecting to, what do they mean in the terms of the JMF audio format properties. (I do understand these are standard audio format commonly used in telecommunication)
UPDATE:
I was more wondering about the format parameter '0 8 101' at the end of
m=audio 12548 RTP/AVP 0 8 101
I know they are referenced from this list, but how do I determine according to the JMF media format which one to use?
Thanks in advance,
Adam Zehavi.
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您可以使用 SDP 中列出的任何编解码器。发送 SDP 的代理声明它支持列出的所有编解码器。
在您提供的 SDP 示例中，您可以开始发送使用 G711 ULAW (PCMU) 或 G711 ALAW (PCMA) 编码的 RTP。
You can use any of the codecs listed in the SDP. The agent that sent the SDP is stating that it supports all of the codecs listed.
In the SDP example you've provided you could start sending RTP encoded with either G711 ULAW (PCMU) or G711 ALAW (PCMA).
我不确定这是否是您所要求的，但是：
I'm not sure if this is what you asked for, but:
经过长时间的搜索和不太理解，我可以回答我的问题。
在我看来，SDP的唯一用途就是让双方向对方说明自己的媒体能力，我没有意识到这是以谈判的形式，我不明白有必要就媒体进行如此深入的谈判，我认为客户端 1 可以提供 X，Y，Z，W，客户端 2 会响应我只能得到 X，W，然后客户端一会说好吧，我向你发送 W 格式...
不知道为什么这很有意义对我来说，我将以这种方式设计我的应用程序的 SDP 包装器，并且仅使用 JMF 格式作为比较，而不是处理 SDP 的排水沟，一遍又一遍，我会尝试设计一个通用的模板将执行所有这些烦人的文本生成方法，使用 JMF 格式数组，就像我认为应该的那样，唯一令我惊讶的是我没有发现任何类似的东西已经制作...
感谢您的所有帮助，如果有人再次想知道这个主题，请开始阅读这个 RFC< /a>
Well after long while of searching and not really understanding, I can answer my question.
In my eyes, the only use for SDP would have been for each side to state to the other his media capabilities, I did not realize it was in the form of negotiation, I didn't understand the need for such a deep negotiation about media, I thought Client 1 could supply X,Y,Z,W, client 2 would response I can only get X,W and then Client one would say ok I send you W format...
don't know why this made perfect sense to me, and I'm going to design my SDP wrapper of my application in this manner, and only to use JMF formats as a comparison instead of dealing with the gutter of the SDP, over and over, I would try to design a general template that would perform all these annoying text generating methods, using JMF format array, just like I think it should be, the only thing I'm surprised is that I didn't find anything like this already made...
Thanks for all your help, and if anyone ever wonder about this subject again, just start reading this RFC