首页 > 软件开发 > 音视频技术 > [转]FLV rtmp 里存在B帧的情况下,time stamp 时间戳应该怎么玩
2014
11-21

[转]FLV rtmp 里存在B帧的情况下,time stamp 时间戳应该怎么玩

FLV  rtmp 里存在B帧的情况下,time stamp 应该怎么玩 ?

先来引用stackoverflow的一篇文章:
CompositionTime Composition time offset
See ISO 14496-12, 8.15.3 for an explanation of composition times. The offset in an FLV file is always in milliseconds

provides the offset between decoding time and composition time. Since decoding time must be less than the composition time, the offsets are expressed as unsigned numbers such that CT(n) = DT(n) + CTTS(n) where CTTS(n) is the (uncompressed) table entry for sample n.

For MPEG-4 H.246 transcoders that deliver I-frame, P-frame, and B-frame NALUs inside an MPEG-2 transport, the resulting packetized elementary streams (PES) are timestamped with presentation time stamps (PTS) and decoder timestamps (DTS) in time units of 1/90000 of a second.

The NALUs come in DTS timestamp order in a repeating pattern like

I P B B B P B B B …

where the intended playback rendering is

I B B B P B B B P …

(This transport strategy ensures that both frames that the B-frame bridges are in the decoder before the B-frame is processed.)

For FLV, the Timestamp (FLV spec p.69) tells when the frame should be fed to the decoder in milliseconds, which is

timestamp = DTS / 90.0

The CompositionTime (FLV spec p.72) tells the renderer when to perform (“compose”) the video frame on the display device in milliseconds after it enters the decoder; thus it is

compositionTime = (PTS – DTS) / 90.0

(Because the PTS >= DTS, this delta is never negative.)

大概知道什么意思了没?再来帖 一张图,从flv的标准文档里扣的:

就是给它赋值 compostionTime即可。

代码是老衲写的,说明技术细节所用,不得转载。 也不准跟老衲索要代码,会假装不在线的。

转自 http://hi.baidu.com/mingyuejingque/item/558dcc16aa29e4623f87cef0

最后编辑:
作者:Carmen
这个作者貌似有点懒,什么都没有留下。