作者： 小武

发布于

sed 对特殊行进行操作

sed -i ‘3s/aaa/fff/’ file                –表示针对file文件中的第三行，将其中的aaa替换为fff

sed -i ‘/xxx/s/aaa/fff/g’ file    –表示针对文件，找出包含xxx的行，并将其中的aaa替换为fff

sed -i ‘1s/[#*]/fff/gp’ file    –表示针对文件第1行，将其中的#号或是*号替换为fff

删除指定文件的上一行
sed -i -e :a -e ‘$!N;s/.*n(.*directory)/1/;ta’ -e ‘P;D’ server.xml

删除指定文件的下一行
sed -i ‘/pattern=”%/{n;d}’ server.xml

发布于

dataframe 对列从新排序使用输出到json的文件的序列要求

 

df[{'vol','open','close','high','low','date'}].to_json(orient='values',path_or_buf='000001_01.sh.json')

 

tushare 返回的数据，生产json时，数据的顺序不对。

为此可以将列进行重新排序。

开始序列如下：

In [42]: dfnew.dtypes
Out[42]: 
vol      float64
open     float64
close    float64
high     float64
low      float64
date      object
dtype: object

 

dfnew = dfnew[['date','open','close','high','low','vol']]

 

In [44]: dfnew.dtypes
Out[44]: 
date      object
open     float64
close    float64
high     float64
low      float64
vol      float64
dtype: object

 

 

发布于

Docker systemctl 不能使用

 

[root@93aba38c7427 /]# systemctl 
System has not been booted with systemd as init system (PID 1). Can't operate.
Failed to connect to bus: Host is down

当使用centos docker时发现不能使用systemctl等命令。

解决方案：

sudo docker run -itd --dns 114.114.114.114  --dns 114.114.115.115  --publish 3380:80   --publish 3322:22   --name centos_xwds_02  --privileged=true   --restart always  --volume /etc/localtime:/etc/localtime   --volume  /mydata:/mydata centos:latest /sbin/init

添加 –privileged=true 初始化程序为/sbin/init

发布于

ffmpeg 转码 vp9 10bit 视频

/libvpx/libvpx$ ./configure –enable-vp9-highbitdepth

make &make install

make ffmpeg

./configure –enable-debug=3 –disable-doc –disable-optimizations –enable-pic –extra-cflags=-fPIC –enable-openssl –enable-libx264 –enable-libx265 –enable-gpl –enable-nonfree –enable-libfreetype –enable-libfdk-aac –enable-libaom –enable-libvpx –enable-libopus

make && make install

ffmpeg -i /mydata/mymedia/mm_test_libx264_30_4096x2304.mp4 -c:v libvpx-vp9 -r 60 -s 4096*2160 -pix_fmt yuv420p10le -t 60 vp9_4096_2160_60fps_yuv420p10le.mkv

 

发布于

ffmpeg 编码x265 10bit 视频

假如x265源码位置如下：

xw@xw-pc:~/mywork/mycode/media/x265/x265$ ls
build COPYING doc readme.rst source

修改文件 x265/source/CMakeLists.txt 找到如下位置将OFF改成ON

if(X64)
# NOTE: We only officially support high-bit-depth compiles of x265
# on 64bit architectures. Main10 plus large resolution plus slow
# preset plus 32bit address space usually means malloc failure. You
# can disable this if(X64) check if you desparately need a 32bit
# build with 10bit/12bit support, but this violates the "shrink wrap
# license" so to speak. If it breaks you get to keep both halves.
# You will need to disable assembly manually.
option(HIGH_BIT_DEPTH "Store pixel samples as 16bit values (Main10/Main12)" ON)
endif(X64)

cmake ../x265/x265/source/

make

make install

编译 ffmpeg

./configure –enable-debug=3 –disable-doc –disable-optimizations –enable-pic –extra-cflags=-fPIC –enable-openssl –enable-libx264 –enable-libx265 –enable-gpl –enable-nonfree –enable-libfreetype –enable-libfdk-aac –enable-libaom –enable-libvpx –enable-libopus

ffmpeg -i /mydata/mymedia/mm_test_libx264_30_4096x2304.mp4 -c:v libx265 -r 60 -s 4096*2160 -pix_fmt yuv420p10le -t 60 h.265_4096_2160_60fps_yuv420p10le.mkv

发布于

mp4 文件 stsd 解析

Sample Description Box

Box Types: ‘stsd’
Container: Sample Table Box (‘stbl’) Mandatory: Yes
Quantity: Exactly one

The sample description table gives detailed information about the coding type used, and any initialization information needed for that coding.

The information stored in the sample description box after the entry‐count is both track‐type specific as documented here, and can also have variants within a track type (e.g. different codings may use different specific information after some common fields, even within a video track).

Which type of sample entry form is used is determined by the media handler, using a suitable form, such as one defined in clause 12, or defined in a derived specification, or registration.

Multiple descriptions may be used within a track.

Note Though the count is 32 bits, the number of items is usually much fewer, and is restricted by the fact that the reference index in the sample table is only 16 bits

If the ‘format’ field of a SampleEntry is unrecognized, neither the sample description itself, nor the associated media samples, shall be decoded.

Note The definition of sample entries specifies boxes in a particular order, and this is usually also followed in derived specifications. For maximum compatibility, writers should construct files respecting the order both within specifications and as implied by the inheritance, whereas readers should be prepared to accept any box order.

All string fields shall be null‐terminated, even if unused. “Optional” means there is at least one null byte.

Entries that identify the format by MIME type, such as a TextSubtitleSampleEntry, TextMetaDataSampleEntry, or SimpleTextSampleEntry, all of which contain a MIME type, may be used to identify the format of streams for which a MIME type applies. A MIME type applies if the contents of the string in the optional configuration box (without its null termination), followed by the contents of a set of samples, starting with a sync sample and ending at the sample immediately preceding a sync sample, are concatenated in their entirety, and the result meets the decoding requirements for documents of that MIME type. Non‐sync samples should be used only if that format specifies the behaviour of ‘progressive decoding’, and then the sample times indicate when the results of such progressive decoding should be presented (according to the media type).

Note The samples in a track that is all sync samples are therefore each a valid document for that MIME type.

In some classes derived from SampleEntry, namespace and schema_location are used both to identify the XML document content and to declare “brand” or profile compatibility. Multiple namespace identifiers indicate that the track conforms to the specification represented by each of the identifiers, some of which may identify supersets of the features present. A decoder should be able to decode all the namespaces in order to be able to decode and present correctly the media associated with this sample entry.

Note Additionally, namespace identifiers may represent performance constraints, such as limits on document size, font size, drawing rate, etc., as well as syntax constraints such as features that are not permitted or ignored.

 

aligned(8) class Box (unsigned int(32) boxtype,
optional unsigned int(8)[16] extended_type) {
unsigned int(32) size;
unsigned int(32) type = boxtype;
if (size==1) {
unsigned int(64) largesize;
} else if (size==0) {
// box extends to end of file
}
if (boxtype==‘uuid’) {
unsigned int(8)[16] usertype = extended_type;
}
}

 

aligned(8) class FullBox(unsigned int(32) boxtype, unsigned int(8) v, bit(24) f)
extends Box(boxtype) {
unsigned int(8)
version = v;
bit(24)
flags = f;
}

 

aligned(8) abstract class SampleEntry (unsigned int(32) format) extends Box(format)
{
    const unsigned int(8)[6] reserved = 0; 
    unsigned int(16) data_reference_index;
}

class BitRateBox extends Box('btrt'){ 
    unsigned int(32) bufferSizeDB; 
    unsigned int(32) maxBitrate; 
    unsigned int(32) avgBitrate;
}


aligned(8) class SampleDescriptionBox (unsigned int(32) handler_type) extends FullBox('stsd', version, 0){
    int i ; // i 为临时变量，不占用空间
    unsigned int(32) entry_count;
    for (i = 1 ; i <= entry_count ; i++){
        SampleEntry();	// an instance of a class derived from SampleEntry
    }
}

参考协议 ISO/IEC 14496-12:2015 page – 170
12.1.3 Sample entry
12.1.3.1
Definition
Video tracks use VisualSampleEntry. // 当handler_type 是视频时，使用VisualSampleEntry

class VisualSampleEntry(codingname) extends SampleEntry (codingname){
unsigned int(16) pre_defined = 0;
const unsigned int(16) reserved = 0;
unsigned int(32)[3] pre_defined = 0;
unsigned int(16) width;
unsigned int(16) height;
template unsigned int(32) horizresolution = 0x00480000; // 72 dpi
template unsigned int(32) vertresolution = 0x00480000; // 72 dpi
const unsigned int(32) reserved = 0;
template unsigned int(16) frame_count = 1;
string[32] compressorname;
template unsigned int(16) depth = 0x0018;
int(16) pre_defined = -1;
// other boxes from derived specifications
CleanApertureBox
clap;
// optional
PixelAspectRatioBox pasp;
// optional
}

000006d0: 00 00 00 01 00 00 01 0b 73 74 62 6c 00 00 00 a7 ……..stbl….
000006e0: 73 74 73 64 00 00 00 00 00 00 00 01 00 00 00 97 stsd…………
000006f0: 61 76 63 31 00 00 00 00 00 00 00 01 00 00 00 00 avc1…………
00000700: 00 00 00 00 00 00 00 00 00 00 00 00 00 0c 00 0c …………….
00000710: 00 48 00 00 00 48 00 00 00 00 00 00 00 01 00 00 .H…H……….
00000720: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …………….
00000730: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 18 …………….
00000740: ff ff 00 00 00 31 61 76 63 43 01 f4 00 0a ff e1 …..1avcC……
00000750: 00 19 67 f4 00 0a 91 9b 2b f2 cb 80 b6 40 00 00 ..g…..+….@..
00000760: 03 00 40 00 00 0c 83 c4 89 65 80 01 00 05 68 eb ..@……e….h.
00000770: e3 c4 48 00 00 00 10 70 61 73 70 00 00 00 01 00 ..H….pasp…..
00000780: 00 00 01 00 00 00 18 73 74 74 73 00 00 00 00 00 …….stts…..
00000790: 00 00 01 00 00 00 01 00 00 0e 10 00 00 00 1c 73 ……………s
000007a0: 74 73 63 00 00 00 00 00 00 00 01 00 00 00 01 00 tsc………….
000007b0: 00 00 01 00 00 00 01 00 00 00 14 73 74 73 7a 00 ………..stsz.
000007c0: 00 00 00 00 00 02 f0 00 00 00 01 00 00 00 14 73 ……………s
000007d0: 74 63 6f 00 00 00 00 00 00 00 01 00 00 00 30 00 tco………..0.
000007e0: 00 01 bc 74 72 61 6b 00 00 00 5c 74 6b 68 64 00 …trak…\tkhd.
000007f0: 00 00 03 00 00 00 00 00 00 00 00 00 00 00 02 00 …………….

size 00 00 00 a7

type 73 74 73 64

version 8  00

flags 24 00 00 00

entry_count 00 00 00 01 == 1 

00 00 00 97 // VisualSampleEntry size 0x97

61 76 63 31 //VisualSampleEntry type avc1

aligned(8) abstract class SampleEntry (unsigned int(32) format) extends Box(format)
{
    const unsigned int(8)[6] reserved = 0; 
    unsigned int(16) data_reference_index;
}

00 00 00 00 00 00  // const unsigned int(8)[6] reserved = 0;

00  01 // unsigned int(16) data_reference_index;

参考协议 ISO/IEC 14496-12:2015 page – 170

class VisualSampleEntry(codingname) extends SampleEntry (codingname){
unsigned int(16) pre_defined = 0;
const unsigned int(16) reserved = 0;
unsigned int(32)[3] pre_defined = 0;
unsigned int(16) width;
unsigned int(16) height;
template unsigned int(32) horizresolution = 0x00480000; // 72 dpi
template unsigned int(32) vertresolution = 0x00480000; // 72 dpi
const unsigned int(32) reserved = 0;
template unsigned int(16) frame_count = 1;
string[32] compressorname;
template unsigned int(16) depth = 0x0018;
int(16) pre_defined = -1;
// other boxes from derived specifications 
CleanApertureBox clap; // optional
PixelAspectRatioBox pasp; // optional
}

000006d0: 00 00 00 01 00 00 01 0b 73 74 62 6c 00 00 00 a7 ……..stbl….
000006e0: 73 74 73 64 00 00 00 00 00 00 00 01 00 00 00 97 stsd…………
000006f0: 61 76 63 31 00 00 00 00 00 00 00 01 00 00 00 00 avc1…………
00000700: 00 00 00 00 00 00 00 00 00 00 00 00 00 0c 00 0c …………….
00000710: 00 48 00 00 00 48 00 00 00 00 00 00 00 01 00 00 .H…H……….
00000720: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …………….
00000730: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 18 …………….
00000740: ff ff 00 00 00 31 61 76 63 43 01 f4 00 0a ff e1 …..1avcC……
00000750: 00 19 67 f4 00 0a 91 9b 2b f2 cb 80 b6 40 00 00 ..g…..+….@..
00000760: 03 00 40 00 00 0c 83 c4 89 65 80 01 00 05 68 eb ..@……e….h.
00000770: e3 c4 48 00 00 00 10 70 61 73 70 00 00 00 01 00 ..H….pasp…..
00000780: 00 00 01 00 00 00 18 73 74 74 73 00 00 00 00 00 …….stts…..
00000790: 00 00 01 00 00 00 01 00 00 0e 10 00 00 00 1c 73 ……………s
000007a0: 74 73 63 00 00 00 00 00 00 00 01 00 00 00 01 00 tsc………….
000007b0: 00 00 01 00 00 00 01 00 00 00 14 73 74 73 7a 00 ………..stsz.
000007c0: 00 00 00 00 00 02 f0 00 00 00 01 00 00 00 14 73 ……………s
000007d0: 74 63 6f 00 00 00 00 00 00 00 01 00 00 00 30 00 tco………..0.
000007e0: 00 01 bc 74 72 61 6b 00 00 00 5c 74 6b 68 64 00 …trak…\tkhd.
000007f0: 00 00 03 00 00 00 00 00 00 00 00 00 00 00 02 00 …………….

00 00 // VisualSampleEntry unsigned int(16) pre_defined = 0;

00 00 // VisualSampleEntry const unsigned int(16) reserved = 0;

00 00 00 00 00 00 00 00 00 00 00 00 // VisualSampleEntry unsigned int(32)[3] pre_defined = 0;

00 0c // VisualSampleEntry unsigned int(16) width;

00 0c // VisualSampleEntry unsigned int(16) height;

00 48 00 00// VisualSampleEntry  template unsigned int(32) horizresolution = 0x00480000; // 72 dpi template unsigned int(32) 

00 48 00 00 // VisualSampleEntry pi template  unsigned int(32) vertresolution = 0x00480000; // 72 dpi const

00 00 00 00 //VisualSampleEntry const unsigned int(32) reserved = 0;

00 01 //VisualSampleEntry template unsigned int(16) frame_count = 1;

00*32 //VisualSampleEntry string[32] compressorname;

00 18 //VisualSampleEntry template unsigned int(16) depth = 0x0018;

ff ff //VisualSampleEntry  int(16) pre_defined = -1;

参考协议 ISO/IEC 14496-15  5.3.3.1 定义如下：

aligned(8) class AVCDecoderConfigurationRecord {
  unsigned int(8) configurationVersion = 1;
  unsigned int(8) AVCProfileIndication;
  unsigned int(8) profile_compatibility;
  unsigned int(8) AVCLevelIndication; 
  bit(6) reserved = '111111'b;
  unsigned int(2) lengthSizeMinusOne; 
  bit(3) reserved = '111'b;
  unsigned int(5) numOfSequenceParameterSets;
  for (i=0; i< numOfSequenceParameterSets;  i++) {
    unsigned int(16) sequenceParameterSetLength ;
    bit(8*sequenceParameterSetLength) sequenceParameterSetNALUnit;
  }
  unsigned int(8) numOfPictureParameterSets;
  for (i=0; i< numOfPictureParameterSets;  i++) {
    unsigned int(16) pictureParameterSetLength;
    bit(8*pictureParameterSetLength) pictureParameterSetNALUnit;
  }
  if( AVCProfileIndication  !=  66  &&  AVCProfileIndication  !=  77  &&
      AVCProfileIndication  !=  88 )
  {
    bit(6) reserved = '111111'b;
    unsigned int(2) chroma_format;
    bit(5) reserved = '11111'b;
    unsigned int(3) bit_depth_luma_minus8;
    bit(5) reserved = '11111'b;
    unsigned int(3) bit_depth_chroma_minus8;
    unsigned int(8) numOfSequenceParameterSetExt;
    for (i=0; i< numOfSequenceParameterSetExt; i++) {
      unsigned int(16) sequenceParameterSetExtLength;
      bit(8*sequenceParameterSetExtLength) sequenceParameterSetExtNALUnit;
    }
  }
}

参考协议 ISO/IEC 14496-15  5.4.2 定义如下：

5.4.2 AVC video stream definition

1.1.1.1 Sample entry name and format

1.1.1.1.1 Definition

Sample Entry and Box Types:  ‘avc1’, ‘avc2’, ‘avc3’, ‘avc4’, ‘avcC’, ‘m4ds’,’btrt’
Container: Sample Description Box (‘stsd’)
Mandatory: An ‘avc1’, ‘avc2’, ‘avc3’ or ‘avc4’ sample entry is mandatory
Quantity: One or more sample entries may be present

An AVC visual sample entry shall contain an AVC Configuration Box, as defined below. This includes an AVCDecoderConfigurationRecord, as defined in ‎5.3.3.1.

An optional BitRateBox may be present in the AVC visual sample entry to signal the bit rate information of the AVC video stream. Extension descriptors that should be inserted into the Elementary Stream Descriptor, when used in MPEG-4, may also be present.

Multiple sample entries may be used, as permitted by the ISO Base Media File Format specification, to indicate sections of video that use different configurations or parameter sets.

The sample entry name ‘avc1’ or ‘avc3’ may only be used when the stream to which this sample entry applies is a compliant and AVC stream as viewed by an AVC decoder operating under the configuration (including profile and level) given in the AVCConfigurationBox. The file format specific structures that resemble NAL units (see ‎Annex A) may be present but shall not be used to access the AVC base data; that is, the AVC data shall not be contained in Aggregators (though they may be included within the bytes referenced by the additional_bytes field) nor referenced by Extractors.

The sample entry name ‘avc2’ or ‘avc4’ may only be used when Extractors or Aggregators (‎Annex A) are required to be supported, and an appropriate Toolset is required (for example, as indicated by the file-type brands). This sample entry type indicates that, in order to form the intended AVC stream, Extractors shall be replaced with the data they are referencing, and Aggregators shall be examined for contained NAL Units. Tier grouping may be present.

1.1.1.1.2 Syntax

// Visual Sequences
class AVCConfigurationBox extends Box(‘avcC’) {
AVCDecoderConfigurationRecord() AVCConfig;
}

class MPEG4ExtensionDescriptorsBox extends Box(‘m4ds’) {
Descriptor Descr[0 .. 255];
}

class AVCSampleEntry() extends VisualSampleEntry (type) {
// type is ‘avc1’ or ‘avc3’
AVCConfigurationBox config;
MPEG4ExtensionDescriptorsBox (); // optional
}

class AVC2SampleEntry() extends VisualSampleEntry (type) {
// type is ‘avc2’ or ‘avc4’
AVCConfigurationBox avcconfig;
MPEG4ExtensionDescriptorsBox descr; // optional
}

1.1.1.1.3 Semantics

Compressorname in the base class VisualSampleEntry indicates the name of the compressor used with the value “\012AVC Coding” being recommended; the first byte is a count of the remaining bytes, here represented by \012, which (being octal 12) is 10 (decimal), the number of bytes in the rest of the string.

config is defined in ‎5.3.3. If a separate parameter set stream is used, numOfSequenceParameterSets and numOfPictureParameterSets shall both be zero.

Descr is a descriptor that should be placed in the ElementaryStreamDescriptor when this stream is used in an MPEG-4 systems context. This does not include SLConfigDescriptor or DecoderConfigDescriptor, but includes the other descriptors in order to be placed after the SLConfigDescriptor.

参考协议 ISO/IEC 14496-15  5.3.3.1 定义如下：

aligned(8) class AVCDecoderConfigurationRecord {
  unsigned int(8) configurationVersion = 1;
  unsigned int(8) AVCProfileIndication;
  unsigned int(8) profile_compatibility;
  unsigned int(8) AVCLevelIndication; 
  bit(6) reserved = '111111'b;
  unsigned int(2) lengthSizeMinusOne; 
  bit(3) reserved = '111'b;
  unsigned int(5) numOfSequenceParameterSets;
  for (i=0; i< numOfSequenceParameterSets;  i++) {
    unsigned int(16) sequenceParameterSetLength ;
    bit(8*sequenceParameterSetLength) sequenceParameterSetNALUnit;
  }
  unsigned int(8) numOfPictureParameterSets;
  for (i=0; i< numOfPictureParameterSets;  i++) {
    unsigned int(16) pictureParameterSetLength;
    bit(8*pictureParameterSetLength) pictureParameterSetNALUnit;
  }
  if( AVCProfileIndication  !=  66  &&  AVCProfileIndication  !=  77  &&
      AVCProfileIndication  !=  88 )
  {
    bit(6) reserved = '111111'b;
    unsigned int(2) chroma_format;
    bit(5) reserved = '11111'b;
    unsigned int(3) bit_depth_luma_minus8;
    bit(5) reserved = '11111'b;
    unsigned int(3) bit_depth_chroma_minus8;
    unsigned int(8) numOfSequenceParameterSetExt;
    for (i=0; i< numOfSequenceParameterSetExt; i++) {
      unsigned int(16) sequenceParameterSetExtLength;
      bit(8*sequenceParameterSetExtLength) sequenceParameterSetExtNALUnit;
    }
  }
}

00000730: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 18 …………….
00000740: ff ff 00 00 00 31 61 76 63 43 01 f4 00 0a ff e1 …..1avcC……
00000750: 00 19 67 f4 00 0a 91 9b 2b f2 cb 80 b6 40 00 00 ..g…..+….@..
00000760: 03 00 40 00 00 0c 83 c4 89 65 80 01 00 05 68 eb ..@……e….h.
00000770: e3 c4 48 00 00 00 10 70 61 73 70 00 00 00 01 00 ..H….pasp…..
00000780: 00 00 01 00 00 00 18 73 74 74 73 00 00 00 00 00 …….stts…..
00000790: 00 00 01 00 00 00 01 00 00 0e 10 00 00 00 1c 73 ……………s
000007a0: 74 73 63 00 00 00 00 00 00 00 01 00 00 00 01 00 tsc………….
000007b0: 00 00 01 00 00 00 01 00 00 00 14 73 74 73 7a 00 ………..stsz.
000007c0: 00 00 00 00 00 02 f0 00 00 00 01 00 00 00 14 73 ……………s
000007d0: 74 63 6f 00 00 00 00 00 00 00 01 00 00 00 30 00 tco………..0.
000007e0: 00 01 bc 74 72 61 6b 00 00 00 5c 74 6b 68 64 00 …trak…\tkhd.
000007f0: 00 00 03 00 00 00 00 00 00 00 00 00 00 00 02 00 …………….

00 00 00 31 // AVCDecoderConfigurationRecord box size

61 76 63 43 // AVCDecoderConfigurationRecord type

01 //AVCDecoderConfigurationRecord  unsigned int(8) configurationVersion = 1;

f4 //AVCDecoderConfigurationRecord unsigned int(8) AVCProfileIndication;

00 // unsigned int(8) profile_compatibility;

0a //unsigned int(8) AVCLevelIndication;

ff // bit(6) reserved = ‘111111’b; unsigned int(2) lengthSizeMinusOne; 

e1 = 1110 0001 // bit(3) reserved = ‘111’b; unsigned int(5) numOfSequenceParameterSets; 即 sps 数量为1

 00 19 //unsigned int(16) sequenceParameterSetLength ;

00 19 67 f4 00 0a 91 9b 2b f2 cb 80 b6 40 00 00 03 00 40 00 00 0c 83 c4 89 65 80 //bit(8*sequenceParameterSetLength) sequenceParameterSetNALUnit; sps data

01 //unsigned int(8) numOfPictureParameterSets;

00 05 // unsigned int(16) sequenceParameterSetLength ;

参考协议 ISO/IEC 14496-12 12.1.4 Pixel Aspect Ratio and Clean Aperture page – 170

00000770: e3 c4 48 00 00 00 10 70 61 73 70 00 00 00 01 00 ..H….pasp…..
00000780: 00 00 01 00 00 00 18 73 74 74 73 00 00 00 00 00 …….stts…..

class PixelAspectRatioBox extends Box(‘pasp’){
    unsigned int(32) hSpacing; 
    unsigned int(32) vSpacing;
}

00 00 00 01 // unsigned int(32) hSpacing;

00 00 00 01 //unsigned int(32) vSpacing;

avc1解析需要协议14496-15

可参考 ：

https://blog.csdn.net/badousuan/article/details/79519862

发布于

mp4 文件 stbl 解析

Sample Table Box

Box Type: ‘stbl’
Container: Media Information Box (‘minf’) Mandatory: Yes
Quantity: Exactly one

The sample table contains all the time and data indexing of the media samples in a track. Using the tables here, it is possible to locate samples in time, determine their type (e.g. I‐frame or not), and determine their size, container, and offset into that container.

If the track that contains the Sample Table Box references no data, then the Sample Table Box does not need to contain any sub‐boxes (this is not a very useful media track).

If the track that the Sample Table Box is contained in does reference data, then the following sub‐boxes are required: Sample Description, Sample Size, Sample To Chunk, and Chunk Offset. Further, the Sample Description Box shall contain at least one entry. A Sample Description Box is required because it contains the data reference index field which indicates which Data Reference Box to use to retrieve the media samples. Without the Sample Description, it is not possible to determine where the media samples are stored. The Sync Sample Box is optional. If the Sync Sample Box is not present, all samples are sync samples.

A.7 provides a narrative description of random access using the structures defined in the Sample Table Box.

aligned(8) class SampleTableBox extends Box(‘stbl’) {
}

000006d0: 00 00 00 01 00 00 01 0b 73 74 62 6c 00 00 00 a7 ……..stbl….
000006e0: 73 74 73 64 00 00 00 00 00 00 00 01 00 00 00 97 stsd…………
000006f0: 61 76 63 31 00 00 00 00 00 00 00 01 00 00 00 00 avc1…………
00000700: 00 00 00 00 00 00 00 00 00 00 00 00 00 0c 00 0c …………….
00000710: 00 48 00 00 00 48 00 00 00 00 00 00 00 01 00 00 .H…H……….
00000720: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 …………….
00000730: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 18 …………….
00000740: ff ff 00 00 00 31 61 76 63 43 01 f4 00 0a ff e1 …..1avcC……
00000750: 00 19 67 f4 00 0a 91 9b 2b f2 cb 80 b6 40 00 00 ..g…..+….@..
00000760: 03 00 40 00 00 0c 83 c4 89 65 80 01 00 05 68 eb ..@……e….h.
00000770: e3 c4 48 00 00 00 10 70 61 73 70 00 00 00 01 00 ..H….pasp…..
00000780: 00 00 01 00 00 00 18 73 74 74 73 00 00 00 00 00 …….stts…..
00000790: 00 00 01 00 00 00 01 00 00 0e 10 00 00 00 1c 73 ……………s
000007a0: 74 73 63 00 00 00 00 00 00 00 01 00 00 00 01 00 tsc………….
000007b0: 00 00 01 00 00 00 01 00 00 00 14 73 74 73 7a 00 ………..stsz.
000007c0: 00 00 00 00 00 02 f0 00 00 00 01 00 00 00 14 73 ……………s
000007d0: 74 63 6f 00 00 00 00 00 00 00 01 00 00 00 30 00 tco………..0.
000007e0: 00 01 bc 74 72 61 6b 00 00 00 5c 74 6b 68 64 00 …trak…\tkhd.
000007f0: 00 00 03 00 00 00 00 00 00 00 00 00 00 00 02 00 …………….

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mp4 文件 dref 解析

Data ReferenceBox

Box Types: ‘dref’
Container: Data Information Box (‘dinf’)
Mandatory: Yes
Quantity: Exactly one

Box Types: ‘url ‘, ‘urn’
Container: Data Information Box (‘dref’)
Mandatory: Yes (at least one of ‘url ‘ or ‘urn ‘ shall be present)
Quantity: One or more
The data reference object contains a table of data references (normally URLs) that declare the location(s) of the media data used within the presentation. The data reference index in the sample description ties entries in this table to the samples in the track. A track may be split over several sources in this way.

If the flag is set indicating that the data is in the same file as this box, then no string (not even an empty one) shall be supplied in the entry field.

The entry_count in the DataReferenceBox shall be 1 or greater; each DataEntryBox within the DataReferenceBox shall be either a DataEntryUrnBox or a DataEntryUrlBox.

NOTE Though the count is 32 bits, the number of items is usually much fewer, and is restricted by the fact that the reference index in the sample table is only 16 bits

When a file that has data entries with the flag set indicating that the media data is in the same file, is split into segments for transport, the value of this flag does not change, as the file is (logically) reassembled after the transport operation.

aligned(8) class DataEntryUrlBox (bit(24) flags) extends FullBox(‘url ‘, version = 0, flags) {
string location;
}

aligned(8) class DataEntryUrnBox (bit(24) flags) extends FullBox(‘urn ‘, version = 0, flags) {
string name;
string location;
}

aligned(8) class DataReferenceBox
extends FullBox(‘dref’, version = 0, 0) {
unsigned int(32) entry_count;
for (i=1; i <= entry_count; i++) {
DataEntryBox(entry_version, entry_flags) data_entry;
}
}

000006b0: 00 00 00 24 64 69 6e 66 00 00 00 1c 64 72 65 66 …$dinf….dref
000006c0: 00 00 00 00 00 00 00 01 00 00 00 0c 75 72 6c 20 …………url
000006d0: 00 00 00 01 00 00 01 0b 73 74 62 6c 00 00 00 a7 ……..stbl….
000006e0: 73 74 73 64 00 00 00 00 00 00 00 01 00 00 00 97 stsd…………

size 00 00 00 1c

vesion 8 00

flags 24 00 00 00

entry_count 32 00 00 00 01

DataEntryUrlBox

000006c0: 00 00 00 00 00 00 00 01 00 00 00 0c 75 72 6c 20 …………url
000006d0: 00 00 00 01 00 00 01 0b 73 74 62 6c 00 00 00 a7 ……..stbl….

size 00 00 00 0c

type 75 72 6c 20 0x20==space

version 0 

flags 00 00 01

 

 

000008d0: 00 00 00 00 00 00 00 24 64 69 6e 66 00 00 00 1c …….$dinf….
000008e0: 64 72 65 66 00 00 00 00 00 00 00 01 00 00 00 0c dref…………
000008f0: 75 72 6c 20 00 00 00 01 00 00 00 a3 73 74 62 6c url ……..stbl