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:AVC10 q8 m% `* |- O4 c1 N
我在搜索编程资料时在微软的msdn上发现的:7 f+ G; g4 L/ x2 S
原文:http://msdn.microsoft.com/en-us/library/dd757808(v=vs.85).aspx
/ K* X. n7 l2 }: t5 `& p+ @2 r FOURCC:AVC1 描述:H.264 bitstream without start codes.
% v' X4 X/ k1 S! D" [9 x9 T, G, Y* \ FOURCC:H264 描述:H.264 bitstream with start codes.
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1 Q7 V! \5 I% Q3 [+ Z6 o H.264 Bitstream with Start Codes
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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.
" C; H' [+ T# e* b9 e( _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. k! ]& ^+ _3 A3 p
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; ^& Q9 {6 A! g! U; o& y3 e H.264 Bitstream Without Start Codes
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B" A0 z2 N+ Y' H 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.
1 i* Z- K1 S% D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。* {/ s7 L4 m- k; p0 [
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。0 C4 Y% }- z8 Y
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