rtmpdump的librtmp时间戳有问题,服务器会断开连接
0x44
0xff 0xff 0xff 0x00 0x01 0x19 0x08
# extended timestamp
0x7f 0xff 0xf8 0x00
# body
0xaf 0x01 0x01 0x40
0x22 0x80 0xa3 0x7f 0xf8 0x85 0x2d 0x2d
0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d
0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d
0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d
0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d
0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d
0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d
0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d
0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d
0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d
0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d
0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d
0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d
0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d
0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d
0x2d 0x2d 0x2d 0x2d
#header
0xc4
# extended timestamp
# error here
#body
0x2d 0x2d 0x2d
0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d
0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d
0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d
0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d
0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d
0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d
0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d
0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d
0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d
0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d
0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d
0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d 0x2d
对于0xC这种后续的chunk包的extended timestamp该不该发,rtmp协议中说是不发,但是FMLE是发的,推流超过4.5小时就需要用extended timestamp了。
rtmpdump里面的librtmp,不会发这个包,(ffmpeg里面用--enable-librtmp就会使用这个rtmp的库),而且是在开始就会发这个包。
6.1.3. Extended Timestamp
有可能是adobe变更了这个协议,也就是说,FMLE给FMS,FMS给flash-player,都是带这个时间戳的。
收包时,服务器端则需要检测下,若接下来的4字节不是extended timestamp,那么就忽略就好了。
发包时,只能采取配置,要么发,要么不发。默认发就好了。
看nginx-rtmp代码:
可见,不管是什么chunk,只要有extended-timestamp,nginx-rtmp都会读这个。所以nginx-rtmp对接FMLE是没有问题的,对接librtmp有问题。
更好的做法是判断下读出来的extended timestamp是否是和之前的一样,如果不是一样说明没有发,就忽略。
nginx-rtmp发包的逻辑:
nginx-rtmp还特意说明了flash客户端就是和rtmp规范不一样。
out->buf->pos就是指向包的第一个chunk,若有extended-timestamp,那么肯定会在第一个包加上extended timestamp;后面还有个th和thsize,就是给后续的type=3的chunk包的,会加上这4字节的extended timestamp:
所以nginx-rtmp收发包都是需要这个extended-timestamp,对于chunk type为3的包。
另外,把chunksize设置大一点,最大是65536,避免发type=3的chunk包,也是一个很好的方法。不过视频的I帧一般较大,超过64KB也有可能。
The maximum chunk size can be 65536 bytes and minimum 128 bytes.
按照这种规则,即type=3的chunk也发extended-timestamp,是没有问题:
FMLE一直没有断开,客户端也没有断开。
服务器端是srs(simple rtmp server),也没有断开:
时间已经超过了24位,使用extended-timestamp:
而nginx呢,是采用第一个包发完全的extended-timestamp,但是后续都是发type=1的chunk,即时间戳差值。