RGB转换为YUV，+的ffmpeg

问题描述

我想下面从我的Flash / AIR应用程序录制现场视频：

I am trying the following to record a live video from my Flash/AIR application:

1. 在我采取了截图（的BitmapData从阶段）每一帧。

2. 我将每个像素YUV格式像这样（V2）

    var file :File = new File(_appUrl + "/creation/output.raw");
    var fs :FileStream = new FileStream();
    fs.open(file, FileMode.WRITE);
    var finalY :ByteArray = new ByteArray();
    var finalU :ByteArray = new ByteArray();
    var finalV :ByteArray = new ByteArray();
    var rect :Rectangle = new Rectangle(0, 0, 600, 700);
    var pixels :ByteArray;
    var pixel :uint;
    var r :uint;
    var g :uint;
    var b :uint;
    _screenBuffer = _screenBuffer.reverse();
    while (_screenBuffer.length > 0)
    {
        pixels = BitmapData(_screenBuffer.pop()).getPixels(rect);
        pixels.position = 0;
        // Convert and save each pixel
        for (var x:int = 0; x < 600; x++)
        {
            for (var y:int = 0; y < 700; y++)
            {
                // Convert to yuv
                pixel = pixels.readUnsignedInt();
                r = pixel >> 16 & 0xff;
                g = pixel >> 8 & 0xff;
                b = pixel & 0xff;
                    // Y' is written for each pixel
                finalY.writeByte(0.257 * r + 0.504 * g + 0.098 * b + 128);
                    // U and V are written once per 2x2 pixel block
                if (x % 2 == 0 && y % 2 == 0)
                {
                    finalU.writeByte(-0.148 * r - 0.291 * g + 0.439 * b + 128);
                    finalV.writeByte(0.439 * r - 0.368 * g - 0.071 * b + 128);
                }
            }
        }
    }
    // Write the converted bytes to the file
    finalY.position = 0;
    finalU.position = 0;
    finalV.position = 0;
    fs.writeBytes(finalY, 0, finalY.length);
    fs.writeBytes(finalU, 0, finalU.length);
    fs.writeBytes(finalV, 0, finalV.length);
    fs.close();

我用的ffmpeg的下面一行将原始文件转换为视频：

I use the following line of ffmpeg to convert the raw file to a video:

ffmpeg -r 30 -pix_fmt yuv420p -s 600x700 -vcodec rawvideo -f rawvideo -i output.raw -y test.mp4

一个视频被创建，但它只是一个烂摊子，几乎没有什么类似记录。我知道，在捕获过程的工作，因为我已经试过了同一个BitmapData截屏的的。

A video is created, but it is simply a mess, barely resembling what was recorded. I know that the capturing process works, as I have tried the same BitmapData "screenshots" with the SimpleFlvWriter.

所以，无论是什么是错的我的转换或与ffmpeg的线，但我不知道。

So, either something is wrong with my conversion or with the ffmpeg line, but I have no idea.

这是什么样的ffmpeg输出创建视频的时候，也许它可以帮助别人：

This is what ffmpeg outputs when creating the video, maybe it can help someone:

libavutil      51. 39.100 / 51. 39.100
libavcodec     54.  3.101 / 54.  3.101
libavformat    54.  1.100 / 54.  1.100
libavdevice    53.  4.100 / 53.  4.100
libavfilter     2. 62.101 /  2. 62.101
libswscale      2.  1.100 /  2.  1.100
libswresample   0.  7.100 /  0.  7.100
libpostproc    52.  0.100 / 52.  0.100
[rawvideo @ 01D39FC0] Estimating duration from bitrate, this may be inaccurate
Input #0, rawvideo, from 'output.raw':
  Duration: N/A, start: 0.000000, bitrate: N/A
    Stream #0:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 600x700, 30 tbr,
30 tbn, 30 tbc
[buffer @ 01D3FEC0] w:600 h:700 pixfmt:yuv420p tb:1/1000000 sar:0/1 sws_param:
[libx264 @ 0375DB80] using cpu capabilities: MMX2 SSE2Fast SSSE3 FastShuffle SSE 4.2 AVX
[libx264 @ 0375DB80] profile High, level 3.1
[libx264 @ 0375DB80] 264 - core 120 r2146 bcd41db - H.264/MPEG-4 AVC codec - Copyleft 2003-2011 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=12 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, mp4, to 'test.mp4':
  Metadata:
    encoder         : Lavf54.1.100
    Stream #0:0: Video: h264 (![0][0][0] / 0x0021), yuv420p, 600x700, q=-1--1, 30 tbn, 30 tbc
Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo -> libx264)
Press [q] to stop, [?] for help
Truncating packet of size 630000 to 1
frame=   48 fps=  0 q=-1.0 Lsize=     157kB time=00:00:01.53 bitrate= 837.3kbits/s
video:156kB audio:0kB global headers:0kB muxing overhead 0.687626%
[libx264 @ 0375DB80] frame I:3     Avg QP:23.15  size: 23480
[libx264 @ 0375DB80] frame P:38    Avg QP:28.80  size:  2169
[libx264 @ 0375DB80] frame B:7     Avg QP:29.61  size:   833
[libx264 @ 0375DB80] consecutive B-frames: 79.2%  4.2%  0.0% 16.7%
[libx264 @ 0375DB80] mb I  I16..4: 41.4%  6.2% 52.4%
[libx264 @ 0375DB80] mb P  I16..4: 10.6%  3.3%  0.9%  P16..4: 68.4%  1.3%  1.2% 0.0%  0.0%    skip:14.2%
[libx264 @ 0375DB80] mb B  I16..4:  0.0%  0.0%  0.0%  B16..8: 13.3%  2.2%  0.7% direct: 1.9%  skip:81.9%  L0:51.6% L1:47.4% BI: 1.0%
[libx264 @ 0375DB80] 8x8 transform intra:16.7% inter:31.2%
[libx264 @ 0375DB80] coded y,uvDC,uvAC intra: 14.7% 25.5% 22.3% inter: 1.0% 4.1% 3.4%
[libx264 @ 0375DB80] i16 v,h,dc,p: 87% 11%  2%  0%
[libx264 @ 0375DB80] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu:  3% 18% 75%  1%  0%  1%  1% 0%  0%
[libx264 @ 0375DB80] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu:  6% 74% 12%  1%  1%  1%  2% 1%  2%
[libx264 @ 0375DB80] i8c dc,h,v,p: 51% 45%  4%  1%
[libx264 @ 0375DB80] Weighted P-Frames: Y:0.0% UV:0.0%
[libx264 @ 0375DB80] ref P L0:  4.6%  0.4% 94.6%  0.3%
[libx264 @ 0375DB80] ref B L0: 96.0%  4.0%
[libx264 @ 0375DB80] ref B L1: 96.5%  3.5%
[libx264 @ 0375DB80] kb/s:793.39

我不是一个真正的codeC专家（刚开始）。），所以我不知道该怎么做的大部分是

I'm not really a codec expert (just starting ;)), so I don't know what to make of most of that.

这里是包含帧和视频输出中的一个的拉链的。什么应可见的是一个绿色的微笑梨，没有任何瑕疵。记住大小是600x700，格式YUV420。最佳观看这样的原始图像文件与IrfanView的，海事组织。不介意噪音，其从推着我的麦克风;）

Here is a zip that contains one of the frames and the video output. What should be visible is a green smiling pear, without any artifacts. Remember the size is 600x700 and the format yuv420. Best to view such raw image files with irfanview, IMO. Don't mind the noise, its from pushing against my microphone ;)

推荐答案

您使用的像素格式

-pix_fmt yuv420p

这在内存

Y1 Y2 Y3 Y4 Y5 Y6 Y7 Y8 U1234 U5678 V1234 V5678

即有U和一个V的4个像素，每个像素的正方形。此外，你有全部的Y第一，那么所有的U和那么所有在V。

ie there is U and one V for each square of 4 pixels. Furthermore, you have all the Y first, then all the U and then all the V.

看来你写

Y1 U1 V1 Y2 U2 V2 ...

有多个像素格式。如果你想使用 YUV420P ，你需要坚持的内存布局。检查维基百科条目上YUV420P

There are multiple pixel formats. If you want to use yuv420p, you need to stick to the memory layout. Check the Wikipedia entry on yuv420p

这篇关于RGB转换为YUV，+的ffmpeg的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！