基于ZedBoard的Webcam设计(五)：x264编码在zedboard上的实现(软编码)

在(原创)基于ZedBoard的Webcam设计(四):MJPG编码和AVI封装中，我们在zed上完成了视频的采集和存储，但是MJPG只是对一帧一帧图片进行编码，编码效率只有10%。x264-snapshot提供了开源x264源代码，已经广泛用于嵌入式解决方案中。本小节将介绍zed上x264-snapshot源码的配置，并在zed上使用High版本、main版本对一个33M的测试视频进行编码，测试编码效率。

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相关阅读：

(原创)基于ZedBoard的Webcam设计(一)：USB摄像头(V4L2接口)的图片采集

(原创)基于ZedBoard的Webcam设计(二)：USB摄像头图片采集+QT显示

(原创)基于ZedBoard的Webcam设计(三)：视频的采集和动态显示

(原创)基于ZedBoard的Webcam设计(四)：MJPG编码和AVI封装

(原创)基于ZedBoard的Webcam设计(五)：x264编码在zedboard上的实现(软编码)

硬件平台：Digilent ZedBoard

开发环境：Windows XP 32 bit + Wmare 8.0 + Ubuntu 10.04 +Qt+ arm-linux-xilinx-gnueabi交叉编译环境

Zedboard linux: Digilent OOB Design

一、x264开源包获取

x264-snapshot提供了开源x264源代码，已经在X86和ARM架构下均已实现。linux下可以使用git获得最新的代码包

git clone git://git.videolan.org/x264.git

也可以通过网页下载：

http://download.videolan.org/pub/videolan/x264/snapshots/

二、配置、安装x264-snapshot

下载到源码后，对其进行配置，以便在后续make时编译出zed上可以运行的可执行程序

1、解压源码包后，进入源码目录

./configure --host=arm-xilinx-linux-gnueabi --prefix=/opt/rcq --enable-shared --disable-asm

congfig之后，设定了host为arm-xilinx-linux-gnueabi，install路径是/opt/rcq

2、修改config.mak文件

针对zed的gcc，需要修改config.mak文件

 1 SRCPATH=. 2 prefix=/opt/rcq 3 exec_prefix=${prefix} 4 bindir=${exec_prefix}/bin 5 libdir=${exec_prefix}/lib 6 includedir=${prefix}/include 7 ARCH=ARM 8 SYS=LINUX 9 CC=arm-xilinx-linux-gnueabi-gcc10 CFLAGS=-Wshadow -O3 -fno-fast-math  -Wall -I. -I$(SRCPATH) -std=gnu99 -fPIC -fomit-frame-pointer -fno-tree-vectorize11 DEPMM=-MM -g012 DEPMT=-MT13 LD=arm-xilinx-linux-gnueabi-gcc -o 14 LDFLAGS= -lm -lpthread15 LIBX264=libx264.a16 AR=arm-xilinx-linux-gnueabi-ar rc 17 RANLIB=arm-xilinx-linux-gnueabi-ranlib18 STRIP=arm-xilinx-linux-gnueabi-strip19 AS=20 ASFLAGS= -DHAVE_ALIGNED_STACK=1 -DPIC -DHIGH_BIT_DEPTH=0 -DBIT_DEPTH=821 RC=22 RCFLAGS=23 EXE=24 HAVE_GETOPT_LONG=125 DEVNULL=/dev/null26 PROF_GEN_CC=-fprofile-generate27 PROF_GEN_LD=-fprofile-generate28 PROF_USE_CC=-fprofile-use29 PROF_USE_LD=-fprofile-use30 default: cli31 install: install-cli32 SOSUFFIX=so33 SONAME=libx264.so.12934 SOFLAGS=-shared -Wl,-soname,$(SONAME)  -Wl,-Bsymbolic35 default: lib-shared36 install: install-lib-shared37 LDFLAGSCLI = 38 CLI_LIBX264 = $(LIBX264)

其中9、13、16、17、18行为修改后的。

3、make

make installmake

完运行库的安装和成执行文件的生成

三、在zed上测试x264

将可执行x264和测试rcq.yuv文件拷贝到zed上，使用默认运行命令

./x264 rcq.yuv --input-res 640x480 -o rcq.flv

其中--input-res 640x480设定输入yuv视频帧的大小，rcq.flv是输出文件，可以设定为.mkv/.mp4/H264等。从控制台可以看到

使用的profile是最高等级High level 3.0，但是的编码速率只有1.40fps……情何以堪……

编码结束后：

生成的rcq.flv文件大小348k，相比较原来的rcq.yuv文件大小33M，压缩率在1%。

可以使用最快编码方式，命令和参数如下

./x264 rcq.yuv --input-res 640x480 -o rcq.flv --no-8x8dct --aq-mode 0 --b-adapt 0 --bframes 0 --no-cabac --no-deblock --no-mbtree --me dia --no-mixed-refs --partitions none --rc-lookahead 0 --ref 1 --scenecut 0 --subme 0 --trellis 0

编码速率能有22fps，这样还凑合。生成的rcq.flv文件大小787K，压缩率在5%。

四、x264命令和参数(fullhelp)

Syntax: x264 [options] -o outfile infileInfile can be raw (in which case resolution is required),  or YUV4MPEG (*.y4m),  or Avisynth if compiled with support (no).  or libav* formats if compiled with lavf support (no) or ffms support (no).Outfile type is selected by filename: .264 -> Raw bytestream .mkv -> Matroska .flv -> Flash Video .mp4 -> MP4 if compiled with GPAC support (no)Output bit depth: 8 (configured at compile time)Options:  -h, --help                  List basic options      --longhelp              List more options      --fullhelp              List all optionsExample usage:      Constant quality mode:            x264 --crf 24 -o <output> <input>      Two-pass with a bitrate of 1000kbps:            x264 --pass 1 --bitrate 1000 -o <output> <input>            x264 --pass 2 --bitrate 1000 -o <output> <input>      Lossless:            x264 --qp 0 -o <output> <input>      Maximum PSNR at the cost of speed and visual quality:            x264 --preset placebo --tune psnr -o <output> <input>      Constant bitrate at 1000kbps with a 2 second-buffer:            x264 --vbv-bufsize 2000 --bitrate 1000 -o <output> <input>Presets:      --profile <string>      Force the limits of an H.264 profile                                  Overrides all settings.                                  - baseline:                                    --no-8x8dct --bframes 0 --no-cabac                                    --cqm flat --weightp 0                                    No interlaced.                                    No lossless.                                  - main:                                    --no-8x8dct --cqm flat                                    No lossless.                                  - high:                                    No lossless.                                  - high10:                                    No lossless.                                    Support for bit depth 8-10.                                  - high422:                                    No lossless.                                    Support for bit depth 8-10.                                    Support for 4:2:0/4:2:2 chroma subsampling.                                  - high444:                                    Support for bit depth 8-10.                                    Support for 4:2:0/4:2:2/4:4:4 chroma subsampling.      --preset <string>       Use a preset to select encoding settings [medium]                                  Overridden by user settings.                                  - ultrafast:                                    --no-8x8dct --aq-mode 0 --b-adapt 0                                    --bframes 0 --no-cabac --no-deblock                                    --no-mbtree --me dia --no-mixed-refs                                    --partitions none --rc-lookahead 0 --ref 1                                    --scenecut 0 --subme 0 --trellis 0                                    --no-weightb --weightp 0                                  - superfast:                                    --no-mbtree --me dia --no-mixed-refs                                    --partitions i8x8,i4x4 --rc-lookahead 0                                    --ref 1 --subme 1 --trellis 0 --weightp 1                                  - veryfast:                                    --no-mixed-refs --rc-lookahead 10                                    --ref 1 --subme 2 --trellis 0 --weightp 1                                  - faster:                                    --no-mixed-refs --rc-lookahead 20                                    --ref 2 --subme 4 --weightp 1                                  - fast:                                    --rc-lookahead 30 --ref 2 --subme 6                                    --weightp 1                                  - medium:                                    Default settings apply.                                  - slow:                                    --b-adapt 2 --direct auto --me umh                                    --rc-lookahead 50 --ref 5 --subme 8                                  - slower:                                    --b-adapt 2 --direct auto --me umh                                    --partitions all --rc-lookahead 60                                    --ref 8 --subme 9 --trellis 2                                  - veryslow:                                    --b-adapt 2 --bframes 8 --direct auto                                    --me umh --merange 24 --partitions all                                    --ref 16 --subme 10 --trellis 2                                    --rc-lookahead 60                                  - placebo:                                    --bframes 16 --b-adapt 2 --direct auto                                    --slow-firstpass --no-fast-pskip                                    --me tesa --merange 24 --partitions all                                    --rc-lookahead 60 --ref 16 --subme 11                                    --trellis 2      --tune <string>         Tune the settings for a particular type of source                              or situation                                  Overridden by user settings.                                  Multiple tunings are separated by commas.                                  Only one psy tuning can be used at a time.                                  - film (psy tuning):                                    --deblock -1:-1 --psy-rd <unset>:0.15                                  - animation (psy tuning):                                    --bframes {+2} --deblock 1:1                                    --psy-rd 0.4:<unset> --aq-strength 0.6                                    --ref {Double if >1 else 1}                                  - grain (psy tuning):                                    --aq-strength 0.5 --no-dct-decimate                                    --deadzone-inter 6 --deadzone-intra 6                                    --deblock -2:-2 --ipratio 1.1                                     --pbratio 1.1 --psy-rd <unset>:0.25                                    --qcomp 0.8                                  - stillimage (psy tuning):                                    --aq-strength 1.2 --deblock -3:-3                                    --psy-rd 2.0:0.7                                  - psnr (psy tuning):                                    --aq-mode 0 --no-psy                                  - ssim (psy tuning):                                    --aq-mode 2 --no-psy\                                  - fastdecode:                                    --no-cabac --no-deblock --no-weightb                                    --weightp 0                                  - zerolatency:                                    --bframes 0 --force-cfr --no-mbtree                                    --sync-lookahead 0 --sliced-threads                                    --rc-lookahead 0      --slow-firstpass        Don't force these faster settings with --pass 1:                                  --no-8x8dct --me dia --partitions none                                  --ref 1 --subme {2 if >2 else unchanged}                                  --trellis 0 --fast-pskipFrame-type options:  -I, --keyint <integer or "infinite"> Maximum GOP size [250]  -i, --min-keyint <integer>  Minimum GOP size [auto]      --no-scenecut           Disable adaptive I-frame decision      --scenecut <integer>    How aggressively to insert extra I-frames [40]      --intra-refresh         Use Periodic Intra Refresh instead of IDR frames  -b, --bframes <integer>     Number of B-frames between I and P [3]      --b-adapt <integer>     Adaptive B-frame decision method [1]                                  Higher values may lower threading efficiency.                                  - 0: Disabled                                  - 1: Fast                                  - 2: Optimal (slow with high --bframes)      --b-bias <integer>      Influences how often B-frames are used [0]      --b-pyramid <string>    Keep some B-frames as references [normal]                                  - none: Disabled                                  - strict: Strictly hierarchical pyramid                                  - normal: Non-strict (not Blu-ray compatible)      --open-gop              Use recovery points to close GOPs                              Only available with b-frames      --no-cabac              Disable CABAC  -r, --ref <integer>         Number of reference frames [3]      --no-deblock            Disable loop filter  -f, --deblock <alpha:beta>  Loop filter parameters [0:0]      --slices <integer>      Number of slices per frame; forces rectangular                              slices and is overridden by other slicing options      --slice-max-size <integer> Limit the size of each slice in bytes      --slice-max-mbs <integer> Limit the size of each slice in macroblocks      --tff                   Enable interlaced mode (top field first)      --bff                   Enable interlaced mode (bottom field first)      --constrained-intra     Enable constrained intra prediction.      --pulldown <string>     Use soft pulldown to change frame rate                                  - none, 22, 32, 64, double, triple, euro (requires cfr input)      --fake-interlaced       Flag stream as interlaced but encode progressive.                              Makes it possible to encode 25p and 30p Blu-Ray                              streams. Ignored in interlaced mode.      --frame-packing <integer> For stereoscopic videos define frame arrangement                                  - 0: checkerboard - pixels are alternatively from L and R                                  - 1: column alternation - L and R are interlaced by column                                  - 2: row alternation - L and R are interlaced by row                                  - 3: side by side - L is on the left, R on the right                                  - 4: top bottom - L is on top, R on bottom                                  - 5: frame alternation - one view per frameRatecontrol:  -q, --qp <integer>          Force constant QP (0-69, 0=lossless)  -B, --bitrate <integer>     Set bitrate (kbit/s)      --crf <float>           Quality-based VBR (0-51) [23.0]      --rc-lookahead <integer> Number of frames for frametype lookahead [40]      --vbv-maxrate <integer> Max local bitrate (kbit/s) [0]      --vbv-bufsize <integer> Set size of the VBV buffer (kbit) [0]      --vbv-init <float>      Initial VBV buffer occupancy [0.9]      --crf-max <float>       With CRF+VBV, limit RF to this value                                  May cause VBV underflows!      --qpmin <integer>       Set min QP [0]      --qpmax <integer>       Set max QP [69]      --qpstep <integer>      Set max QP step [4]      --ratetol <float>       Tolerance of ABR ratecontrol and VBV [1.0]      --ipratio <float>       QP factor between I and P [1.40]      --pbratio <float>       QP factor between P and B [1.30]      --chroma-qp-offset <integer>  QP difference between chroma and luma [0]      --aq-mode <integer>     AQ method [1]                                  - 0: Disabled                                  - 1: Variance AQ (complexity mask)                                  - 2: Auto-variance AQ (experimental)      --aq-strength <float>   Reduces blocking and blurring in flat and                              textured areas. [1.0]  -p, --pass <integer>        Enable multipass ratecontrol                                  - 1: First pass, creates stats file                                  - 2: Last pass, does not overwrite stats file                                  - 3: Nth pass, overwrites stats file      --stats <string>        Filename for 2 pass stats ["x264_2pass.log"]      --no-mbtree             Disable mb-tree ratecontrol.      --qcomp <float>         QP curve compression [0.60]      --cplxblur <float>      Reduce fluctuations in QP (before curve compression) [20.0]      --qblur <float>         Reduce fluctuations in QP (after curve compression) [0.5]      --zones <zone0>/<zone1>/...  Tweak the bitrate of regions of the video                              Each zone is of the form                                  <start frame>,<end frame>,<option>                                  where <option> is either                                      q=<integer> (force QP)                                  or  b=<float> (bitrate multiplier)      --qpfile <string>       Force frametypes and QPs for some or all frames                              Format of each line: framenumber frametype QP                              QP is optional (none lets x264 choose). Frametypes: I,i,K,P,B,b.                                  K=<I or i> depending on open-gop setting                              QPs are restricted by qpmin/qpmax.Analysis:  -A, --partitions <string>   Partitions to consider ["p8x8,b8x8,i8x8,i4x4"]                                  - p8x8, p4x4, b8x8, i8x8, i4x4                                  - none, all                                  (p4x4 requires p8x8. i8x8 requires --8x8dct.)      --direct <string>       Direct MV prediction mode ["spatial"]                                  - none, spatial, temporal, auto      --no-weightb            Disable weighted prediction for B-frames      --weightp <integer>     Weighted prediction for P-frames [2]                                  - 0: Disabled                                  - 1: Weighted refs                                  - 2: Weighted refs + Duplicates      --me <string>           Integer pixel motion estimation method ["hex"]                                  - dia: diamond search, radius 1 (fast)                                  - hex: hexagonal search, radius 2                                  - umh: uneven multi-hexagon search                                  - esa: exhaustive search                                  - tesa: hadamard exhaustive search (slow)      --merange <integer>     Maximum motion vector search range [16]      --mvrange <integer>     Maximum motion vector length [-1 (auto)]      --mvrange-thread <int>  Minimum buffer between threads [-1 (auto)]  -m, --subme <integer>       Subpixel motion estimation and mode decision [7]                                  - 0: fullpel only (not recommended)                                  - 1: SAD mode decision, one qpel iteration                                  - 2: SATD mode decision                                  - 3-5: Progressively more qpel                                  - 6: RD mode decision for I/P-frames                                  - 7: RD mode decision for all frames                                  - 8: RD refinement for I/P-frames                                  - 9: RD refinement for all frames                                  - 10: QP-RD - requires trellis=2, aq-mode>0                                  - 11: Full RD: disable all early terminations      --psy-rd <float:float>  Strength of psychovisual optimization ["1.0:0.0"]                                  #1: RD (requires subme>=6)                                  #2: Trellis (requires trellis, experimental)      --no-psy                Disable all visual optimizations that worsen                              both PSNR and SSIM.      --no-mixed-refs         Don't decide references on a per partition basis      --no-chroma-me          Ignore chroma in motion estimation      --no-8x8dct             Disable adaptive spatial transform size  -t, --trellis <integer>     Trellis RD quantization. [1]                                  - 0: disabled                                  - 1: enabled only on the final encode of a MB                                  - 2: enabled on all mode decisions      --no-fast-pskip         Disables early SKIP detection on P-frames      --no-dct-decimate       Disables coefficient thresholding on P-frames      --nr <integer>          Noise reduction [0]      --deadzone-inter <int>  Set the size of the inter luma quantization deadzone [21]      --deadzone-intra <int>  Set the size of the intra luma quantization deadzone [11]                                  Deadzones should be in the range 0 - 32.      --cqm <string>          Preset quant matrices ["flat"]                                  - jvt, flat      --cqmfile <string>      Read custom quant matrices from a JM-compatible file                                  Overrides any other --cqm* options.      --cqm4 <list>           Set all 4x4 quant matrices                                  Takes a comma-separated list of 16 integers.      --cqm8 <list>           Set all 8x8 quant matrices                                  Takes a comma-separated list of 64 integers.      --cqm4i, --cqm4p, --cqm8i, --cqm8p <list>                              Set both luma and chroma quant matrices      --cqm4iy, --cqm4ic, --cqm4py, --cqm4pc <list>                              Set individual quant matricesVideo Usability Info (Annex E):The VUI settings are not used by the encoder but are merely suggestions tothe playback equipment. See doc/vui.txt for details. Use at your own risk.      --overscan <string>     Specify crop overscan setting ["undef"]                                  - undef, show, crop      --videoformat <string>  Specify video format ["undef"]                                  - component, pal, ntsc, secam, mac, undef      --range <string>        Specify color range ["auto"]                                  - auto, tv, pc      --colorprim <string>    Specify color primaries ["undef"]                                  - undef, bt709, bt470m, bt470bg                                    smpte170m, smpte240m, film      --transfer <string>     Specify transfer characteristics ["undef"]                                  - undef, bt709, bt470m, bt470bg, linear,                                    log100, log316, smpte170m, smpte240m      --colormatrix <string>  Specify color matrix setting ["???"]                                  - undef, bt709, fcc, bt470bg                                    smpte170m, smpte240m, GBR, YCgCo      --chromaloc <integer>   Specify chroma sample location (0 to 5) [0]      --nal-hrd <string>      Signal HRD information (requires vbv-bufsize)                                  - none, vbr, cbr (cbr not allowed in .mp4)      --pic-struct            Force pic_struct in Picture Timing SEI      --crop-rect <string>    Add 'left,top,right,bottom' to the bitstream-level                              cropping rectangleInput/Output:  -o, --output <string>       Specify output file      --muxer <string>        Specify output container format ["auto"]                                  - auto, raw, mkv, flv      --demuxer <string>      Specify input container format ["auto"]                                  - auto, raw, y4m      --input-fmt <string>    Specify input file format (requires lavf support)      --input-csp <string>    Specify input colorspace format for raw input                              - valid csps for `raw' demuxer:                                i420, yv12, nv12, i422, yv16, nv16, i444, yv24, bgr, bgra, rgb      --output-csp <string>   Specify output colorspace ["i420"]                                  - i420, i422, i444, rgb      --input-depth <integer> Specify input bit depth for raw input      --input-range <string>  Specify input color range ["auto"]                                  - auto, tv, pc      --input-res <intxint>   Specify input resolution (width x height)      --index <string>        Filename for input index file      --sar width:height      Specify Sample Aspect Ratio      --fps <float|rational>  Specify framerate      --seek <integer>        First frame to encode      --frames <integer>      Maximum number of frames to encode      --level <string>        Specify level (as defined by Annex A)      --bluray-compat         Enable compatibility hacks for Blu-ray support  -v, --verbose               Print stats for each frame      --no-progress           Don't show the progress indicator while encoding      --quiet                 Quiet Mode      --log-level <string>    Specify the maximum level of logging ["info"]                                  - none, error, warning, info, debug      --psnr                  Enable PSNR computation      --ssim                  Enable SSIM computation      --threads <integer>     Force a specific number of threads      --lookahead-threads <integer> Force a specific number of lookahead threads      --sliced-threads        Low-latency but lower-efficiency threading      --thread-input          Run Avisynth in its own thread      --sync-lookahead <integer> Number of buffer frames for threaded lookahead      --non-deterministic     Slightly improve quality of SMP, at the cost of repeatability      --cpu-independent       Ensure exact reproducibility across different cpus,                                  as opposed to letting them select different algorithms      --asm <integer>         Override CPU detection      --no-asm                Disable all CPU optimizations      --visualize             Show MB types overlayed on the encoded video      --dump-yuv <string>     Save reconstructed frames      --sps-id <integer>      Set SPS and PPS id numbers [0]      --aud                   Use access unit delimiters      --force-cfr             Force constant framerate timestamp generation      --tcfile-in <string>    Force timestamp generation with timecode file      --tcfile-out <string>   Output timecode v2 file from input timestamps      --timebase <int/int>    Specify timebase numerator and denominator                 <integer>    Specify timebase numerator for input timecode file                              or specify timebase denominator for other input      --dts-compress          Eliminate initial delay with container DTS hackFiltering:      --vf, --video-filter <filter0>/<filter1>/... Apply video filtering to the input file      Filter options may be specified in <filter>:<option>=<value> format.      Available filters:      crop:left,top,right,bottom            removes pixels from the edges of the frame      select_every:step,offset1[,...]            apply a selection pattern to input frames            step: the number of frames in the pattern            offsets: the offset into the step to select a frame            see: http://avisynth.org/mediawiki/Select#SelectEvery

五、关于YUV420的格式说明

YUV格式有两大类：planar和packed。对于planar的YUV格式，先连续存储所有像素点的Y，紧接着存储所有像素点的U，随后是所有像素点的V。对于packed的YUV格式，每个像素点的Y,U,V是连续交*存储的。一般的录像程序是先从摄像头得到yuv420 planar的数据，然后编码成h264格式 帧，最后存储成3gp/mpeg等格式的视频文件。以720×488大小图象YUV420 planar为例，其存储格式是：共大小为(720×480×3>>1)字节，分为三个部分:Y,U和VY分量：    (720×480)个字节  U(Cb)分量：(720×480>>2)个字节V(Cr)分量：(720×480>>2)个字节三个部分内部均是行优先存储，三个部分之间是Y,U,V 顺序存储。即YUV数据的0－－720×480字节是Y分量值，           720×480－－720×480×5/4字节是U分量           720×480×5/4 －－720×480×3/2字节是V分量。一副w*h的yuv420图像数据的大小为w*h*1.5。4 ：2： 2 和4：2：0 转换：最简单的方式：YUV4:2:2 ---> YUV4:2:0  Y不变，将U和V信号值在行(垂直方向)在进行一次隔行抽样。YUV4:2:0 ---> YUV4:2:2  Y不变，将U和V信号值的每一行分别拷贝一份形成连续两行数据。

六、测试视频

=====================================================

0、x264-snapshots:http://download.videolan.org/pub/videolan/x264/snapshots/

1、zed可执行文件：x264.rar

2、测试yuv文件：rcq.part1.rarrcq.part2.rar

3、其他通用测试yuv序列：http://www.cipr.rpi.edu/resource/sequences/sif.html