一、实验要求
1.将不同的视频序列编码为.264文件
2.固定码率,以不同的GOP长度及形状编码
GOP=15,2B帧;GOP=12,2B帧,GOP=9,2B帧
GOP=4,1B帧;GOP=12,无B帧;GOP=1,全I帧
3.相同的GOP长度及形状,不同的码率
用码流分析软件检查所生成的码流中各种编码模式和运动矢量等信息
4.用播放器观看所生成码流的质量
生成率失真曲线
二、实验代码部分
# Files ########################################################################################## InputFile = "1mother-daughter_qcif.yuv" # Input sequence "foreman_part_qcif.yuv" InputHeaderLength = 0 # If the inputfile has a header, state it's length in byte here StartFrame = 0 # Start frame for encoding. (0-N) FramesToBeEncoded = 30 # Number of frames to be coded 3******alter by zml******* FrameRate = 30.0 # Frame Rate per second (0.1-100.0) Enable32Pulldown = 0 # Enable 'hard' 3:2 pulldown (modifying the inpur data) # 0 = disabled # 1 = A, B, Bt|Cb, Ct|Db, D # 2 = A, B, C, Ct|Db, D SEIVUI32Pulldown = 0 # Enable 3:2 pulldown through VUI and SEI metadata signaling. Five methods are supported: # 0 = disabled # 1 = A, Bt|Bb, Bt|Cb, Ct|Cb, D # 2 = A, B, C, C, D # 3 = At|Ab, Bt|Bb, Bt|Cb, Ct|Cb, Dt|Db # 4 = A, Bt|Bb, Bt|Cb, Ct|Db, Dt|Db # 5 = At|Ab, Bt|Bb, Bt|Cb, Ct|Db, Dt|Db SourceWidth = 176 # Source frame width 176******alter by zml******** SourceHeight = 144 # Source frame height144*****alter by zml******* SourceResize = 0 # Resize source size for output OutputWidth = 176 # Output frame width 176*****alter by zml***** OutputHeight = 144 # Output frame height144*****alter by zml***** ProcessInput = 0 # Filter Input Sequence Interleaved = 0 # 0: Planar input, 1: Packed input PixelFormat = 0 # Pixel Format for 422 packed inputs # 0: UYVY # 1: YUY2/YUYV # 2: YVYU # 3: BGR (Unsupported) # 4: V210 (Video Clarity) StandardRange = 0 # 0: Standard range 1: Full range (RGB input) VideoCode = 1 # Video codes for RGB ==> YUV conversions # 0 = NULL, # 1 = ITU_REC709, # 2 = CCIR_601, # 3 = FCC, # 4 = ITU_REC624BG, # 5 = SMPTE_170M, # 6 = SMPTE_240M, # 7 = SMPTE_260M, # 8 = ITU_REC709_EXACT TraceFile = "1mother-daughter2.txt" # Trace file *****alter by zml***** ReconFile = "1mother-daughter_rec2.yuv" # Reconstruction YUV file*****alter by zml****** OutputFile = "1mother-daughter2.264" # Bitstream*****alter by zml****** StatsFile = "1mother-daughter2.dat" # Coding statistics file*******alter by zml***** NumberOfViews = 1 # Number of views to encode (1=1 view, 2=2 views) View1ConfigFile = "encoder_view1.cfg" # Config file name for second view ########################################################################################## …… # Encoder Control ########################################################################################## Grayscale = 0 # Encode in grayscale (Currently only works for 8 bit YUV 420 input) ProfileIDC = 100 # Profile IDC (66=baseline, 77=main, 88=extended; FREXT Profiles: 100=High, 110=High 10, 122=High 4:2:2, 244=High 4:4:4, 44=CAVLC 4:4:4 Intra, 118=Multiview High Profile, 128=Stereo High Profile) IntraProfile = 0 # Activate Intra Profile for FRExt (0: false, 1: true) # (e.g. ProfileIDC=110, IntraProfile=1 => High 10 Intra Profile) LevelIDC = 40 # Level IDC (e.g. 20 = level 2.0) IntraPeriod = 15 # Period of I-pictures (0=only first)0*****alter by zml****** IDRPeriod = 0 # Period of IDR pictures (0=only first) AdaptiveIntraPeriod = 1 # Adaptive intra period AdaptiveIDRPeriod = 0 # Adaptive IDR period IntraDelay = 0 # Intra (IDR) picture delay (i.e. coding structure of PPIPPP... ) EnableIDRGOP = 0 # Support for IDR closed GOPs (0: disabled, 1: enabled) EnableOpenGOP = 1 # Support for open GOPs (0: disabled, 1: enabled)0*****alter by zml****** QPISlice = 28 # Quant. param for I Slices (0-51) QPPSlice = 28 # Quant. param for P Slices (0-51) FrameSkip = 2 # Number of frames to be skipped in input (e.g 2 will code every third frame).0 **********alter by zml***************************************************** # Note that this now excludes intermediate (i.e. B) coded pictures …… # B Slices ########################################################################################## NumberBFrames = 2 # Number of B coded frames inserted (0=not used)7*****alter by zml****** PReplaceBSlice = 0 # Replace B-coded slices with P-coded slices when NumberBFrames>0 QPBSlice = 30 # Quant. param for B slices (0-51) BRefPicQPOffset = -1 # Quantization offset for reference B coded pictures (-51..51) DirectModeType = 1 # Direct Mode Type (0:Temporal 1:Spatial) DirectInferenceFlag = 1 # Direct Inference Flag (0: Disable 1: Enable) BList0References = 0 # B slice List 0 reference override (0 disable, N <= NumberReferenceFrames) BList1References = 1 # B slice List 1 reference override (0 disable, N <= NumberReferenceFrames) # 1 List1 reference is usually recommended for normal GOP Structures. # A larger value is usually more appropriate if a more flexible # structure is used (i.e. using HierarchicalCoding) BReferencePictures = 0 # Referenced B coded pictures (0=off, 1=B references for secondary layer, 2=B references for primary layer) HierarchicalCoding = 2 # B hierarchical coding (0= off, 1= 2 layers, 2= 2 full hierarchy, 3 = explicit)*********alter by zml******* HierarchyLevelQPEnable = 1 # Adjust QP based on hierarchy level (in increments of 1). Overrides BRefPicQPOffset behavior.(0=off, 1=on) …… #################Rate control ########################################################## RateControlEnable = 1 # 0 Disable, 1 Enable0**************alter by zml*************** Bitrate = 30000 # Bitrate(bps)45020*********alter by zml********** InitialQP = 0 # Initial Quantization Parameter for the first I frame # InitialQp depends on two values: Bits Per Picture, # and the GOP length BasicUnit = 0 # Number of MBs in the basic unit # should be a fraction of the total number # of MBs in a frame ("0" sets a BU equal to a frame) ChannelType = 0 # type of channel( 1=time varying channel; 0=Constant channel) RCUpdateMode = 2 # Rate Control type. Modes supported :0**********alter by zml********** # 0 = original JM rate control, # 1 = rate control that is applied to all frames regardless of the slice type, # 2 = original plus intelligent QP selection for I and B slices (including Hierarchical), # 3 = original + hybrid quadratic rate control for I and B slice using bit rate statistics ……
三、实验结果分析
1.将264文件解码得到相应的yuv文件
2.固定码率,以不同的GOP长度及形状编码
GOP=15,2B帧;
GOP=12,2B帧;
GOP=9,2B帧 ;
GOP=4,1B帧;
GOP=12,无B帧;
GOP=1,全I帧
2.相同的GOP长度及形状,不同的码率
GOP=12,2B帧;
800kb/s、600kb/s
3.用码流分析软件检查所生成的码流中各种编码模式和运动矢量等信息
4.用播放器观看所生成码流的质量
5.生成率失真曲线如下:
分析实验结果:在GOP长度小时,B帧数量越少视频质量越差;
在GOP长度大时,B帧数量越少视频质量越好;
码流越大,视频质量越好,但在码流较小区间,psnr上升得快;随着码流越来越大,psnr上升变慢。