Apple的HLS中的PES数据包中的访问单元如何对齐? [英] How are access units aligned within PES packets in Apple's HLS?

问题描述

Apple是否指定了?一个PES数据包有效载荷应放入多少个访问单元?

Does Apple specify this? How many access units should one put in a PES packet payload?

此外，我想知道PES数据包中存在哪些前缀起始码(如果有).我假设访问单元中第一个NAL单元之前的那个是无用的，因此不能放置.对吧?

Also, I'm wondering which prefix start codes (if any) are present in PES packets. I assume that the one preceding the first NAL unit within an access unit is useless and mustn't be put. Right?

我想知道它是如何专门在HLS中完成的-不一定是其他MPEG-2 TS应用程序.

I'd like to know how it's done specifically in HLS - not necessarily any other MPEG-2 TS application.

推荐答案

我想知道它是如何在HLS中具体完成的-不一定 任何其他MPEG-2 TS应用程序.

I'd like to know how it's done specifically in HLS - not necessarily any other MPEG-2 TS application.

HLS是标准的MPEG-2 TS流. HLS的操作没有任何不同，只限于单个音频和单一视频流.并将编解码器限制为AVC/AAC/MP3

HLS is a standard MPEG-2 TS stream. HLS does not do it any differently, except limit to a single audio and singe video stream. And limit codecs to AVC/AAC/MP3

对于其余的答案，我将假定您所指的是AVC编解码器. (AAC和MP3有不同的答案)

For the rest of the answers, I will assume you are referring to the AVC codec. (AAC and and MP3 have different answers)

一个PES数据包有效载荷应放入多少个访问单元?

How many access units should one put in a PES packet payload?

一个.但是，为了提高效率，最后一个NALU可能会在TS边界处被截断，其余的会在下一个PES的开始处优先到下一个AU.这是可选的，但会降低比特率.

One. However for efficiency, the last NALU may be truncated on a TS boundary, and the remainder prepended to the next AU at the start of the next PES. This is optional, but it does reduce bitrate.

我想知道PES中存在哪些前缀起始码(如果有) 包.

I'm wondering which prefix start codes (if any) are present in PES packets.

MPEGTS需要附件B样式的开始代码.每个NALU之前都有一个起始代码.一个AU将有多个NALU，因为在mpegts中需要AUD.

MPEGTS requires annex B style start codes. One start code before every NALU. An AU will have several NALUs as AUDs are required in mpegts.

我假设访问中第一个NAL单元之前的那个 单位是无用的，不能放.对吧?

I assume that the one preceding the first NAL unit within an access unit is useless and mustn't be put. Right?

完全错误.每个NALU必须以起始代码开头

Completely wrong. Every NALU must begin with a start code,

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