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I'm trying to process an MP4 which contains video NAL that are using a strange code in the header, and no start code prefix. It looks like that (by frame number):

01:00-00-37-3F-65-B8-4F-DF
02:00-00-00-02-09-30-00-00
03:00-00-00-02-09-30-00-00
04:00-00-00-02-09-30-00-00
05:00-00-00-02-09-30-00-00
[etc]    

Then each 60 frames, it looks like this:

61:00-00-00-02-09-10-00-00

So the inter-frame rate seems to be set to 60.

First frame (01) could also begin like this as I cannot really parse it:

01:00-00-00-00-00-00-00-10-00-00-37-3F-65-B8-4F-DF

What are these headers, and is there a section in the H.264 standard in which I could refer? They are sometime followed by audio (sync-ed).

[EDIT]

Also, further infos: this is produced in WP8, which is using DM355 encoder.

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2 回答 2

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MP4 不使用附件 B。因此没有起始代码。每个 NALU 的前 4 个字节是大端格式的 NALU 的大小。

例如。00-00-00-02-09-10-00-00

这是类型 9 的 2 字节 NALU。9 是访问单元分隔符

要获得 SPS/PPS,您必须从 avcC atom 读取额外数据。

你可以在这里阅读更多: http ://www.szatmary.org/blog/25

于 2013-08-15T03:03:55.870 回答
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我认为它们是压缩的关键帧。似乎每 60 秒出现一次关键帧。不确定音频,它似乎相当不一致。

于 2013-08-15T00:43:45.997 回答