v3_CN_DVR
SRS支持将RTMP流录制成FLV或MP4文件。下面的描述以FLV为例，但是对MP4也是一样的。
DVR作为SRS3的核心功能，永远开启DVR。
参考：Build
DVR的难点在于写入flv和文件命名，SRS的做法是随机生成文件名，用户可以使用http-callback方式，使用外部程序记录这个文件名，或者改成自己要的文件命名方式。
当然也可以修改SRS代码，这种做法不推荐，c操作文件名比较麻烦。还是用外部辅助系统做会很方便。
DVR的配置文件说明：
vhost your_vhost {
# DVR RTMP stream to file,
# start to record to file when encoder publish,
# reap flv/mp4 according by specified dvr_plan.
dvr {
# whether enabled dvr features
# default: off
enabled on;
# the filter for dvr to apply to.
# all, dvr all streams of all apps.
# <app>/<stream>, apply to specified stream of app.
# for example, to dvr the following two streams:
# live/stream1 live/stream2
# default: all
dvr_apply all;
# the dvr plan. canbe:
# session reap flv/mp4 when session end(unpublish).
# segment reap flv/mp4 when flv duration exceed the specified dvr_duration.
# @remark The plan append is removed in SRS3+, for it's no use.
# default: session
dvr_plan session;
# the dvr output path, *.flv or *.mp4.
# we supports some variables to generate the filename.
# [vhost], the vhost of stream.
# [app], the app of stream.
# [stream], the stream name of stream.
# [2006], replace this const to current year.
# [01], replace this const to current month.
# [02], replace this const to current date.
# [15], replace this const to current hour.
# [04], replace this const to current minute.
# [05], replace this const to current second.
# [999], replace this const to current millisecond.
# [timestamp],replace this const to current UNIX timestamp in ms.
# @remark we use golang time format "2006-01-02 15:04:05.999" as "[2006]-[01]-[02]_[15].[04].[05]_[999]"
# for example, for url rtmp://ossrs.net/live/livestream and time 2015-01-03 10:57:30.776
# 1. No variables, the rule of SRS1.0(auto add [stream].[timestamp].flv as filename):
# dvr_path ./objs/nginx/html;
# =>
# dvr_path ./objs/nginx/html/live/livestream.1420254068776.flv;
# 2. Use stream and date as dir name, time as filename:
# dvr_path /data/[vhost]/[app]/[stream]/[2006]/[01]/[02]/[15].[04].[05].[999].flv;
# =>
# dvr_path /data/ossrs.net/live/livestream/2015/01/03/10.57.30.776.flv;
# 3. Use stream and year/month as dir name, date and time as filename:
# dvr_path /data/[vhost]/[app]/[stream]/[2006]/[01]/[02]-[15].[04].[05].[999].flv;
# =>
# dvr_path /data/ossrs.net/live/livestream/2015/01/03-10.57.30.776.flv;
# 4. Use vhost/app and year/month as dir name, stream/date/time as filename:
# dvr_path /data/[vhost]/[app]/[2006]/[01]/[stream]-[02]-[15].[04].[05].[999].flv;
# =>
# dvr_path /data/ossrs.net/live/2015/01/livestream-03-10.57.30.776.flv;
# 5. DVR to mp4:
# dvr_path ./objs/nginx/html/[app]/[stream].[timestamp].mp4;
# =>
# dvr_path ./objs/nginx/html/live/livestream.1420254068776.mp4;
# @see https://github.com/ossrs/srs/wiki/v3_CN_DVR#custom-path
# @see https://github.com/ossrs/srs/wiki/v3_CN_DVR#custom-path
# segment,session apply it.
# default: ./objs/nginx/html/[app]/[stream].[timestamp].flv
dvr_path ./objs/nginx/html/[app]/[stream].[timestamp].flv;
# the duration for dvr file, reap if exceed, in seconds.
# segment apply it.
# session,append ignore.
# default: 30
dvr_duration 30;
# whether wait keyframe to reap segment,
# if off, reap segment when duration exceed the dvr_duration,
# if on, reap segment when duration exceed and got keyframe.
# segment apply it.
# session,append ignore.
# default: on
dvr_wait_keyframe on;
# about the stream monotonically increasing:
# 1. video timestamp is monotonically increasing,
# 2. audio timestamp is monotonically increasing,
# 3. video and audio timestamp is interleaved monotonically increasing.
# it's specified by RTMP specification, @see 3. Byte Order, Alignment, and Time Format
# however, some encoder cannot provides this feature, please set this to off to ignore time jitter.
# the time jitter algorithm:
# 1. full, to ensure stream start at zero, and ensure stream monotonically increasing.
# 2. zero, only ensure stream start at zero, ignore timestamp jitter.
# 3. off, disable the time jitter algorithm, like atc.
# apply for all dvr plan.
# default: full
time_jitter full;
# on_dvr, never config in here, should config in http_hooks.
# for the dvr http callback, @see http_hooks.on_dvr of vhost hooks.callback.srs.com
# @read https://github.com/ossrs/srs/wiki/v3_CN_DVR#http-callback
# @read https://github.com/ossrs/srs/wiki/v3_CN_DVR#http-callback
}
}DVR的计划即决定什么时候关闭flv文件，打开新的flv文件，主要的录制计划包括：
- session：按照session来关闭flv文件，即编码器停止推流时关闭flv，整个session录制为一个flv。
- segment：按照时间分段录制，flv文件时长配置为dvr_duration和dvr_wait_keyframe。注意：若不按关键帧切flv（即dvr_wait_keyframe配置为off），所以会导致后面的flv启动时会花屏。
- time_jitter: 时间戳抖动算法。full使用完全的时间戳矫正；zero只是保证从0开始；off不矫正时间戳。
- dvr_path: 录制的路径，规则参考下一章。
参考conf/dvr.segment.conf和conf/dvr.session.conf配置实例。
DVR的apply决定了是否对某个流开启dvr，默认的all是对所有开启。 这个功能是SRS实现nginx提供的control module的一个基础，而且更丰富。 也就是可以支持用户调用http raw api控制是否以及何时DVR。 参考351
Apply可以对多个流进行录制，譬如对live/stream1和live/stream2录制，可以配置成：
vhost xxx {
dvr {
dvr_apply live/stream1 live/stream2;
}
}
我们可以自定义DVR的路径和文件名，规则如下：
- 按年月日以及流信息生成子目录。便于做软链，或者避免一个目录的文件太多（貌似超过几万linux会支持不了）。
- 按日期和时间以及流信息生成文件名。便于搜索。
- 提供日期和时间，以及流信息的变量，以中括号代表变量。
- 保留目前的方式，按照时间戳生成文件名，保存在一个文件夹。若没有指定文件名（只指定了目录），则默认使用
[stream].[timestamp].flv作为文件名，和目前保持一致。
关于日期和时间的变量，参考了GO的时间格式化字符串，譬如2006代表YYYY这种，比较方便：
2006-01-02 15:04:05.999
DVR支持的变量包括：
- 年：[2006]，将这个字符串替换为年份。
- 月：[01]，将这个字符串替换成月份。
- 日：[02]，将这个字符串替换成日期。
- 时：[15]，将这个字符串替换成小时。
- 分：[04]，将这个字符串替换成分。
- 秒：[05)，将这个字符串替换成秒。
- 毫秒：[999]，将这个字符串替换成毫秒。
- 时间戳：[timestamp]，将这个字符串替换成UNIX时间戳，单位是毫秒。
- 流相关变量，参考转码：[vhost], [app], [stream]
下面的例子说明了替换方式, url是rtmp://ossrs.net/live/livestream，time是2015-01-03 10:57:30.776
-
没有变量，SRS1.0方式（自动添加
[stream].[timestamp].flv作为文件名）：- dvr_path ./objs/nginx/html;
- =>
- dvr_path ./objs/nginx/html/live/livestream.1420254068776.flv;
-
按流和年月日分目录，时间作为文件名：
- dvr_path /data/[vhost]/[app]/[stream]/[2006]/[01]/[02]/[15].[04].[05].[999].flv;
- =>
- dvr_path /data/ossrs.net/live/livestream/2015/01/03/10.57.30.776.flv;
-
按流和年月分目录，日和时间作为文件名：
- dvr_path /data/[vhost]/[app]/[stream]/[2006]/[01]/[02]-[15].[04].[05].[999].flv;
- =>
- dvr_path /data/ossrs.net/live/livestream/2015/01/03-10.57.30.776.flv;
-
按vhost/app和年月分目录，流名称、日和时间作为文件名：
- dvr_path /data/[vhost]/[app]/[2006]/[01]/[stream]-[02]-[15].[04].[05].[999].flv;
- =>
- dvr_path /data/ossrs.net/live/2015/01/livestream-03-10.57.30.776.flv;
-
按app分目录，流和时间戳作为文件名（SRS1.0方式）：
- dvr_path /data/[app]/[stream].[timestamp].flv;
- =>
- dvr_path /data/live/livestream.1420254068776.flv;
打开http_hooks的on_dvr配置：
vhost your_vhost {
dvr {
enabled on;
dvr_path ./objs/nginx/html/[app]/[stream]/[2006]/[01]/[02]/[15].[04].[05].[999].flv;
dvr_plan segment;
dvr_duration 30;
dvr_wait_keyframe on;
}
http_hooks {
enabled on;
on_dvr http://127.0.0.1:8085/api/v1/dvrs;
}
}
api-server的日志：
[2015-01-03 15:25:48][trace] post to dvrs, req={"action":"on_dvr","client_id":108,"ip":"127.0.0.1","vhost":"__defaultVhost__","app":"live","stream":"livestream","cwd":"/home/winlin/git/simple-rtmp-server/trunk","file":"./objs/nginx/html/live/livestream/2015/1/3/15.25.18.442.flv"}
[2015-01-03 15:25:48][trace] srs on_dvr: client id=108, ip=127.0.0.1, vhost=__defaultVhost__, app=live, stream=livestream, cwd=/home/winlin/git/simple-rtmp-server/trunk, file=./objs/nginx/html/live/livestream/2015/1/3/15.25.18.442.flv
127.0.0.1 - - [03/Jan/2015:15:25:48] "POST /api/v1/dvrs HTTP/1.1" 200 1 "" "SRS(Simple RTMP Server)2.0.88"
更多HTTP回调的信息，请参考 HttpCallback
关于DVR的bug：
改变dvr配置后reload，会导致dvr重启，即关闭当前dvr文件后重新应用dvr配置。
Winlin 2015.1