FFMPEG RGB 无损转换视频

Question

FFMPEG RGB 无损转换视频

4

我在FFMPEG文档、论坛和这里都找不到很多答案，遇到了一些困难。

我的目标是压缩一个屏幕捕获的视频，但只使用RGB数据。

我目前采取的步骤是：

ffmpeg -f avfoundation -pix_fmt 0rgb -r "30" -i "1" -vcodec libx264rgb -pix_fmt rgb24 -crf 0 -t 25 -q 0 -y ~/Desktop/RGB.mkv 

south-58-45:~ danielcarter$ ffmpeg -f avfoundation -pix_fmt 0rgb -r "30" -i "1" -vcodec libx264rgb -pix_fmt rgb24 -crf 0 -t 170 -q 0 -y -v info ~/Desktop/output.mkv
ffmpeg version 3.3 Copyright (c) 2000-2017 the FFmpeg developers
  built with Apple LLVM version 8.1.0 (clang-802.0.41)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/3.3 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-libmp3lame --enable-libx264 --enable-libxvid --enable-opencl --disable-lzma --enable-vda
  libavutil      55. 58.100 / 55. 58.100
  libavcodec     57. 89.100 / 57. 89.100
  libavformat    57. 71.100 / 57. 71.100
  libavdevice    57.  6.100 / 57.  6.100
  libavfilter     6. 82.100 /  6. 82.100
  libavresample   3.  5.  0 /  3.  5.  0
  libswscale      4.  6.100 /  4.  6.100
  libswresample   2.  7.100 /  2.  7.100
  libpostproc    54.  5.100 / 54.  5.100
[avfoundation @ 0x7fc39d004c00] Stream #0: not enough frames to estimate rate; consider increasing probesize
Input #0, avfoundation, from '1':
  Duration: N/A, start: 175270.249500, bitrate: N/A
    Stream #0:0: Video: rawvideo ([0]RGB / 0x42475200), 0rgb, 1440x900, 1000k tbr, 1000k tbn, 1000k tbc
Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo (native) -> h264 (libx264rgb))
Press [q] to stop, [?] for help
[libx264rgb @ 0x7fc39d13ea00] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 AVX2 LZCNT BMI2
[libx264rgb @ 0x7fc39d13ea00] profile High 4:4:4 Predictive, level 4.0, 4:4:4 8-bit
[libx264rgb @ 0x7fc39d13ea00] 264 - core 148 r2748 97eaef2 - H.264/MPEG-4 AVC codec - Copyleft 2003-2016 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x1:0x111 me=hex subme=7 psy=0 mixed_ref=1 me_range=16 chroma_me=1 trellis=0 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=0 chroma_qp_offset=0 threads=6 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc=cqp mbtree=0 qp=0
Output #0, matroska, to '/Users/danielcarter/Desktop/output.mkv':
  Metadata:
    encoder         : Lavf57.71.100
    Stream #0:0: Video: h264 (libx264rgb) (H264 / 0x34363248), rgb24, 1440x900, q=-1--1, 30 fps, 1k tbn, 30 tbc
    Metadata:
      encoder         : Lavc57.89.100 libx264rgb
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
frame= 5100 fps= 30 q=-1.0 Lsize=   12167kB time=00:02:49.96 bitrate= 586.4kbits/s speed=0.999x    
video:12134kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.267659%
[libx264rgb @ 0x7fc39d13ea00] frame I:21    Avg QP: 0.00  size:430796
[libx264rgb @ 0x7fc39d13ea00] frame P:5079  Avg QP: 0.00  size:   665
[libx264rgb @ 0x7fc39d13ea00] mb I  I16..4: 61.3%  0.0% 38.7%
[libx264rgb @ 0x7fc39d13ea00] mb P  I16..4:  0.1%  0.0%  0.0%  P16..4:  0.0%  0.0%  0.0%  0.0%  0.0%    skip:99.9%
[libx264rgb @ 0x7fc39d13ea00] 8x8 transform intra:0.0% inter:11.2%
[libx264rgb @ 0x7fc39d13ea00] coded y,u,v intra: 48.0% 31.6% 29.0% inter: 0.0% 0.0% 0.0%
[libx264rgb @ 0x7fc39d13ea00] i16 v,h,dc,p: 76% 22%  2%  0%
[libx264rgb @ 0x7fc39d13ea00] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 46% 35%  7%  2%  2%  1%  1%  1%  3%
[libx264rgb @ 0x7fc39d13ea00] Weighted P-Frames: Y:0.0% UV:0.0%
[libx264rgb @ 0x7fc39d13ea00] ref P L0: 83.1%  6.4%  5.3%  5.2%
[libx264rgb @ 0x7fc39d13ea00] kb/s:584.71

这是我在Mac上捕获屏幕的方法。据我所知，这会创建一个无损文件，我已经比较了一些屏幕截图来证实这一点。接下来的步骤是我认为存在问题的地方。因为我想对原始的RGB数据进行压缩处理，所以我需要将MKV文件转换为RGB文件。

ffmpeg -i ~/Desktop/RGB.mkv -c:v rawvideo -pix_fmt rgb24 -crf 0 -ss 00:00:03 -to 00:02:01 -q 0 -y ~/Desktop/out.rgb

south-58-45:~ danielcarter$ ffmpeg -i ~/Desktop/output.mkv -c:v rawvideo -pix_fmt rgb24 -crf 0 -ss 00:00:03 -to 00:02:01 -q 0 -y ~/Desktop/out.rgb
ffmpeg version 3.3 Copyright (c) 2000-2017 the FFmpeg developers
  built with Apple LLVM version 8.1.0 (clang-802.0.41)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/3.3 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-libmp3lame --enable-libx264 --enable-libxvid --enable-opencl --disable-lzma --enable-vda
  libavutil      55. 58.100 / 55. 58.100
  libavcodec     57. 89.100 / 57. 89.100
  libavformat    57. 71.100 / 57. 71.100
  libavdevice    57.  6.100 / 57.  6.100
  libavfilter     6. 82.100 /  6. 82.100
  libavresample   3.  5.  0 /  3.  5.  0
  libswscale      4.  6.100 /  4.  6.100
  libswresample   2.  7.100 /  2.  7.100
  libpostproc    54.  5.100 / 54.  5.100
Input #0, matroska,webm, from '/Users/danielcarter/Desktop/output.mkv':
  Metadata:
    ENCODER         : Lavf57.71.100
  Duration: 00:02:50.00, start: 0.000000, bitrate: 586 kb/s
    Stream #0:0: Video: h264 (High 4:4:4 Predictive), gbrp(tv, gbr/unknown/unknown, progressive), 1440x900, 30 fps, 30 tbr, 1k tbn, 60 tbc (default)
    Metadata:
      ENCODER         : Lavc57.89.100 libx264rgb
      DURATION        : 00:02:50.000000000
Codec AVOption crf (Select the quality for constant quality mode) specified for output file #0 (/Users/danielcarter/Desktop/out.rgb) has not been used for any stream. The most likely reason is either wrong type (e.g. a video option with no video streams) or that it is a private option of some encoder which was not actually used for any stream.
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> rawvideo (native))
Press [q] to stop, [?] for help
Output #0, rawvideo, to '/Users/danielcarter/Desktop/out.rgb':
  Metadata:
    encoder         : Lavf57.71.100
    Stream #0:0: Video: rawvideo (RGB[24] / 0x18424752), rgb24, 1440x900, q=2-31, 933120 kb/s, 30 fps, 30 tbn, 30 tbc (default)
    Metadata:
      DURATION        : 00:02:50.000000000
      encoder         : Lavc57.89.100 rawvideo
frame= 3540 fps=111 q=-0.0 Lsize=13440938kB time=00:01:58.00 bitrate=933120.0kbits/s speed=3.68x    
video:13440938kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.000000%

有了这个，我就可以成功地压缩和解压缩。然后我得到一个可播放的工作文件;

ffmpeg -f rawvideo -vcodec rawvideo -s 1440x900 -r 30 -pix_fmt rgb24 -i ~/Desktop/out.rgb -c:v libx264rgb -pix_fmt rgb24 -x264opts keyint=300:min-keyint=300:no-scenecut -y -crf 0 ~/Desktop/rgbplay.mkv

south-58-45:~ danielcarter$ ffmpeg -f rawvideo -vcodec rawvideo -s 1440x900 -r 30 -pix_fmt rgb24 -i ~/Desktop/out.rgb -c:v libx264rgb -pix_fmt rgb24 -x264opts keyint=300:min-keyint=300:no-scenecut -y -crf 0 ~/Desktop/rgbplay.mkv
ffmpeg version 3.3 Copyright (c) 2000-2017 the FFmpeg developers
  built with Apple LLVM version 8.1.0 (clang-802.0.41)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/3.3 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-libmp3lame --enable-libx264 --enable-libxvid --enable-opencl --disable-lzma --enable-vda
  libavutil      55. 58.100 / 55. 58.100
  libavcodec     57. 89.100 / 57. 89.100
  libavformat    57. 71.100 / 57. 71.100
  libavdevice    57.  6.100 / 57.  6.100
  libavfilter     6. 82.100 /  6. 82.100
  libavresample   3.  5.  0 /  3.  5.  0
  libswscale      4.  6.100 /  4.  6.100
  libswresample   2.  7.100 /  2.  7.100
  libpostproc    54.  5.100 / 54.  5.100
[rawvideo @ 0x7fb1f9002600] Estimating duration from bitrate, this may be inaccurate
Input #0, rawvideo, from '/Users/danielcarter/Desktop/out.rgb':
  Duration: 00:01:58.00, start: 0.000000, bitrate: 933120 kb/s
    Stream #0:0: Video: rawvideo (RGB[24] / 0x18424752), rgb24, 1440x900, 933120 kb/s, 30 tbr, 30 tbn, 30 tbc
Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo (native) -> h264 (libx264rgb))
Press [q] to stop, [?] for help
[libx264rgb @ 0x7fb1f9010c00] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 AVX2 LZCNT BMI2
[libx264rgb @ 0x7fb1f9010c00] profile High 4:4:4 Predictive, level 4.0, 4:4:4 8-bit
[libx264rgb @ 0x7fb1f9010c00] 264 - core 148 r2748 97eaef2 - H.264/MPEG-4 AVC codec - Copyleft 2003-2016 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x1:0x111 me=hex subme=7 psy=0 mixed_ref=1 me_range=16 chroma_me=1 trellis=0 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=0 chroma_qp_offset=0 threads=6 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=0 weightp=2 keyint=300 keyint_min=151 scenecut=0 intra_refresh=0 rc=cqp mbtree=0 qp=0
Output #0, matroska, to '/Users/danielcarter/Desktop/rgbplay.mkv':
  Metadata:
    encoder         : Lavf57.71.100
    Stream #0:0: Video: h264 (libx264rgb) (H264 / 0x34363248), rgb24, 1440x900, q=-1--1, 30 fps, 1k tbn, 30 tbc
    Metadata:
      encoder         : Lavc57.89.100 libx264rgb
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
frame= 3540 fps= 64 q=-1.0 Lsize=    8319kB time=00:01:57.96 bitrate= 577.7kbits/s speed=2.13x    
video:8297kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.273154%
[libx264rgb @ 0x7fb1f9010c00] frame I:12    Avg QP: 0.00  size:437670
[libx264rgb @ 0x7fb1f9010c00] frame P:3528  Avg QP: 0.00  size:   919
[libx264rgb @ 0x7fb1f9010c00] mb I  I16..4: 61.9%  0.0% 38.1%
[libx264rgb @ 0x7fb1f9010c00] mb P  I16..4:  0.1%  0.0%  0.0%  P16..4:  0.0%  0.0%  0.0%  0.0%  0.0%    skip:99.8%
[libx264rgb @ 0x7fb1f9010c00] 8x8 transform intra:0.0% inter:15.1%
[libx264rgb @ 0x7fb1f9010c00] coded y,u,v intra: 49.7% 36.5% 33.7% inter: 0.0% 0.0% 0.0%
[libx264rgb @ 0x7fb1f9010c00] i16 v,h,dc,p: 73% 25%  1%  0%
[libx264rgb @ 0x7fb1f9010c00] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 45% 36%  7%  2%  2%  2%  2%  1%  3%
[libx264rgb @ 0x7fb1f9010c00] Weighted P-Frames: Y:0.0% UV:0.0%
[libx264rgb @ 0x7fb1f9010c00] ref P L0: 81.3%  7.7%  6.7%  4.3%
[libx264rgb @ 0x7fb1f9010c00] kb/s:575.96

但这里我有像素差异。我的猜测是在某个地方进行了RGB-YUV-RGB转换，但我聪明不到哪里去。

这里有一张并排的两个截图，显示出它们之间的差异；

像素差异

如果需要更多信息，我也可以提供。谢谢！

- DCDCDC

您能提供使用 -v info 参数运行上述命令行时 ffmpeg 可执行文件的完整未剪辑输出吗？特别是，如果有 swscale 的设置，那么看到它会很有趣。 - Ronald S. Bultje

添加了输出 - DCDCDC

你的MKV被标记为具有TV范围。RGB格式应该是pc/full。 - Gyan

@Mulvya 我该怎么设置呢？我发现有 out_range 选项，但它显示为无法识别的选项。 - DCDCDC

它被标记为有限制并不是问题（尽管对于gdigrub最近已经修复），因为ffmpeg不支持有限范围RGB。 - Валерий Заподовников

1个回答

网页内容由stack overflow 提供, 点击上面的

可以查看英文原文，
原文链接

- DCDCDC · Accepted Answer

我通过删除一步骤成功使其工作。从mkv->rgb的转换产生了问题，它使用gbrp作为像素格式，在整个屏幕上创建了轻微的颜色差异。感谢Mulvya指出了范围标记，否则我就不知道该去哪里查看。

为了使此工作正常，我使用以下代码直接捕获RGB：

ffmpeg -f avfoundation -pix_fmt 0rgb -color_range 2 -r "30" -i "1" -vcodec rawvideo -pix_fmt rgb24 -color_range 2 -t 210 -q 0 -y -v info ~/Desktop/output.rgb

然后可以使用以下方式将其转换为MKV文件以进行播放：

ffmpeg -report -f rawvideo -vcodec rawvideo -s 1440x900 -r 30 -pix_fmt rgb24 -color_range 2 -i ~/Desktop/output.rgb -c:v libx264rgb -pix_fmt rgb24 -ss 00:00:04 -to 00:02:02 -color_range 2 -x264opts crf=0 -y  ~/Desktop/rgbplay.mkv

感谢您的帮助，我现在可以安心睡觉了，哈哈。