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
/ |1 V% B% U: s6 K: p, O3 h( S我在搜索编程资料时在微软的msdn上发现的:
! X5 D' K! b b7 h6 a0 ^ 原文:http://msdn.microsoft.com/en-us/library/dd757808(v=vs.85).aspx4 D, C- {* X5 T+ b' f, M
FOURCC:AVC1 描述:H.264 bitstream without start codes.
. W1 U" w1 ?/ j2 x; s. C FOURCC:H264 描述:H.264 bitstream with start codes.3 t! L: d' K& E+ E. d4 p$ p% a
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H.264 Bitstream with Start Codes
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* U: c6 b. Y, Y ]7 ]/ t I2 {( A 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.
; ?; \3 q T2 Y/ Q5 R' x7 a) g" [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.$ l6 \# J1 W! x& U( x% U0 I
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H.264 Bitstream Without Start Codes
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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 J6 Q' G2 j; b$ |3 |$ j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。
b8 d& }: ~* e6 _9 a4 a! C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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