TA的每日心情 | 奋斗 2020-5-6 08:48 |
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签到天数: 140 天 [LV.7]常住居民III
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我一直疑问为什么有些视频解码时显示格式是:H264,大部分又是:AVC1
" C0 F, b' _# s9 G( p% i我在搜索编程资料时在微软的msdn上发现的:
( j# p' v/ P- l; M. i 原文:http://msdn.microsoft.com/en-us/library/dd757808(v=vs.85).aspx! }0 `0 d" F, q
FOURCC:AVC1 描述:H.264 bitstream without start codes.* A4 r% g7 }# d1 g/ ]- q* f
FOURCC:H264 描述:H.264 bitstream with start codes.* ?1 {4 G- w0 U! g
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H.264 Bitstream with Start Codes. C) \/ A# \5 F) M9 i. m7 ?
: a5 ?! [% \0 k" k H.264 bitstreams that are transmitted over the air, or contained in MPEG-2 program or transport streams, or recorded on HD-DVD, are formatted as described in Annex B of ITU-T Rec. H.264. According to this specification, the bitstream consists of a sequence of network abstraction layer units (NALUs), each of which is prefixed with a start code equal to 0x000001 or 0x00000001.
( G |4 R- K- s: b8 t这段话的大致意思是:带有开始码的H.264视频一般是用于无线发射、有线广播或者HD-DVD中的。这些数据流的开始都有一个开始码:0x000001 或者 0x00000001.
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) ]' V& g3 W' J H.264 Bitstream Without Start Codes x! A1 {% w+ d! [- z
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The MP4 container format stores H.264 data without start codes. Instead, each NALU is prefixed by a length field, which gives the length of the NALU in bytes. The size of the length field can vary, but is typically 1, 2, or 4 bytes.
4 p9 `, y- w4 I# X" C) v这段话的大致意思是:没有开始码的H.264视频主要是存储在MP4格式的文件中的。它的数据流的开始是1、2或者4个字节表示长度数据。) v2 S( R" G& `' g7 ~4 p: N9 B3 r1 O
原文中的"NALU"简单说是H.264格式中的最基本的单元,是一个数据包。
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