使用ffmpeg重新编码视频时，这非常快。但是当使用-filter_complex命令时，该过程会减慢到实时。这个过程是绑定到CPU还是GPU？有没有人知道是否有任何方法可以加快使用GPU的速度？
完整的电话如下：
ffmpeg.exe
-i video_0_0.mp4 -i video_0_1.mp4 -i video_0_2.mp4 -i video_0_3.mp4
-filter_complex
"color=c=black:size=1920x1080 [base];
[0:v] setpts=PTS-STARTPTS, scale=960x540 [upperleft];
[1:v] setpts=PTS-STARTPTS, scale=960x540 [upperright];
[2:v] setpts=PTS-STARTPTS, scale=960x540 [lowerleft];
[3:v] setpts=PTS-STARTPTS, scale=960x540 [lowerright];
[base][upperleft] overlay=shortest=1 [tmp1];
[tmp1][upperright] overlay=shortest=1:x=960 [tmp2];
[tmp2][lowerleft] overlay=shortest=1:y=540 [tmp3];
[tmp3][lowerright] overlay=shortest=1:x=960:y=540"
-q 4 -y
"test.mp4"
输出命令：
ffmpeg.exe -i video_0_0.mp4 -i video_0_1.mp4 -i video_0_2.mp4 -i video_0_3.mp4 -filter_complex "color=c=black:size=1920x1080 [base]; [0:v] setpts=PTS-STARTPTS, scale=960x540 [upperleft]; [1:v] setpts=PTS-STARTPTS, scale=960x540 [upperright]; [2:v] setpts=PTS-STARTPTS, scale=960x540 [lowerleft]; [3:v] setpts=PTS-STARTPTS, scale=960x540 [lowerright]; [base][upperleft] overlay=shortest=1 [tmp1]; [tmp1][upperright] overlay=shortest=1:x=960 [tmp2]; [tmp2][lowerleft] overlay=shortest=1:y=540 [tmp3]; [tmp3][lowerright] overlay=shortest=1:x=960:y=540" -q 4 -y "test.mp4"
ffmpeg version 3.2.4 Copyright (c) 2000-2017 the FFmpeg developers
built with gcc 6.3.0 (GCC)
configuration: --enable-gpl --enable-version3 --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-nvenc --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-zlib
libavutil 55. 34.101 / 55. 34.101
libavcodec 57. 64.101 / 57. 64.101
libavformat 57. 56.101 / 57. 56.101
libavdevice 57. 1.100 / 57. 1.100
libavfilter 6. 65.100 / 6. 65.100
libswscale 4. 2.100 / 4. 2.100
libswresample 2. 3.100 / 2. 3.100
libpostproc 54. 1.100 / 54. 1.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'video_0_0.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf57.3.100
Duration: 00:00:05.80, start: 0.000000, bitrate: 14 kb/s
Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuvj420p(pc), 1280x720 [SAR 1:1 DAR 16:9], 12 kb/s, 10 fps, 10 tbr, 10240 tbn, 20 tbc (default)
Metadata:
handler_name : VideoHandler
[h264 @ 000000000275a300] left block unavailable for requested intra mode
[h264 @ 000000000275a300] error while decoding MB 0 21, bytestream 927
[h264 @ 000000000275a300] concealing 1969 DC, 1969 AC, 1969 MV errors in I frame
Input #1, mov,mp4,m4a,3gp,3g2,mj2, from 'video_0_1.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
title : Session streamed with GStreamer
encoder : Lavf57.3.100
comment : rtsp-server
Duration: 00:00:09.76, start: 0.000000, bitrate: 106 kb/s
Stream #1:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuvj420p(pc, bt709), 1280x720 [SAR 1:1 DAR 16:9], 104 kb/s, 24.90 fps, 25 tbr, 90k tbn, 180k tbc (default)
Metadata:
handler_name : VideoHandler
[h264 @ 0000000002a2fb40] error while decoding MB 73 20, bytestream -7
[h264 @ 0000000002a2fb40] concealing 1976 DC, 1976 AC, 1976 MV errors in I frame
Input #2, mov,mp4,m4a,3gp,3g2,mj2, from 'video_0_2.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
title : Session streamed with GStreamer
encoder : Lavf57.3.100
comment : rtsp-server
Duration: 00:00:09.76, start: 0.000000, bitrate: 83 kb/s
Stream #2:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuvj420p(pc, bt709), 1280x720 [SAR 1:1 DAR 16:9], 81 kb/s, 25.21 fps, 25 tbr, 90k tbn, 180k tbc (default)
Metadata:
handler_name : VideoHandler
[h264 @ 0000000002779920] error while decoding MB 22 29, bytestream -7
[h264 @ 0000000002779920] concealing 1307 DC, 1307 AC, 1307 MV errors in I frame
Input #3, mov,mp4,m4a,3gp,3g2,mj2, from 'video_0_3.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
title : Session streamed with GStreamer
encoder : Lavf57.3.100
comment : rtsp-server
Duration: 00:00:09.40, start: 0.000000, bitrate: 44 kb/s
Stream #3:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuvj420p(pc, bt709), 1280x720 [SAR 1:1 DAR 16:9], 41 kb/s, 25.21 fps, 25 tbr, 90k tbn, 180k tbc (default)
Metadata:
handler_name : VideoHandler
[swscaler @ 000000000295a5e0] deprecated pixel format used, make sure you did set range correctly
[swscaler @ 00000000029a64c0] deprecated pixel format used, make sure you did set range correctly
[swscaler @ 00000000029d89c0] deprecated pixel format used, make sure you did set range correctly
[swscaler @ 0000000002a7a160] deprecated pixel format used, make sure you did set range correctly
[libx264 @ 0000000002a42080] -qscale is ignored, -crf is recommended.
[libx264 @ 0000000002a42080] using SAR=1/1
[libx264 @ 0000000002a42080] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 AVX2 LZCNT BMI2
[libx264 @ 0000000002a42080] profile High, level 4.0
[libx264 @ 0000000002a42080] 264 - core 148 r2762 90a61ec - H.264/MPEG-4 AVC codec - Copyleft 2003-2017 - 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=6 lookahead_threads=1 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=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, mp4, to 'test.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf57.56.101
Stream #0:0: Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], q=-1--1, 25 fps, 12800 tbn, 25 tbc (default)
Metadata:
encoder : Lavc57.64.101 libx264
Side data:
cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
Stream mapping:
Stream #0:0 (h264) -> setpts
Stream #1:0 (h264) -> setpts
Stream #2:0 (h264) -> setpts
Stream #3:0 (h264) -> setpts
overlay -> Stream #0:0 (libx264)
Press [q] to stop, [?] for help
[h264 @ 0000000002b12980] left block unavailable for requested intra mode
[h264 @ 0000000002b12980] error while decoding MB 0 21, bytestream 927
[h264 @ 0000000002b12980] concealing 1969 DC, 1969 AC, 1969 MV errors in I frame
[h264 @ 0000000002b14b40] error while decoding MB 73 20, bytestream -7
[h264 @ 0000000002b14b40] concealing 1976 DC, 1976 AC, 1976 MV errors in I frame
[h264 @ 00000000029195e0] error while decoding MB 22 29, bytestream -7
[h264 @ 00000000029195e0] concealing 1307 DC, 1307 AC, 1307 MV errors in I frame
[h264 @ 0000000002b15000] left block unavailable for requested intra4x4 mode -1 0x
[h264 @ 0000000002b15000] error while decoding MB 0 18, bytestream 293
[h264 @ 0000000002b15000] concealing 2209 DC, 2209 AC, 2209 MV errors in I frame
[h264 @ 0000000002b13800] left block unavailable for requested intra modeeed= 0x
[h264 @ 0000000002b13800] error while decoding MB 0 10, bytestream 1778
[h264 @ 0000000002b13800] concealing 2849 DC, 2849 AC, 2849 MV errors in I frame
[h264 @ 000000000291c600] left block unavailable for requested intra modeeed= 0x
[h264 @ 000000000291c600] error while decoding MB 0 32, bytestream 597
[h264 @ 000000000291c600] concealing 1089 DC, 1089 AC, 1089 MV errors in I frame
[h264 @ 0000000002b12e60] error while decoding MB 9 13, bytestream -5807.7kbits/s speed=0.0985x
[h264 @ 0000000002b12e60] concealing 2600 DC, 2600 AC, 2600 MV errors in I frame
[h264 @ 0000000002b12980] left block unavailable for requested intra4x4 mode -1/s speed=0.46x
[h264 @ 0000000002b12980] error while decoding MB 0 3, bytestream 1575
[h264 @ 0000000002b12980] concealing 3409 DC, 3409 AC, 3409 MV errors in I frame
[h264 @ 0000000002b159a0] left block unavailable for requested intra mode
[h264 @ 0000000002b159a0] error while decoding MB 0 14, bytestream 213
[h264 @ 0000000002b159a0] concealing 2529 DC, 2529 AC, 2529 MV errors in I frame
[h264 @ 0000000002918c40] error while decoding MB 63 30, bytestream -761.8kbits/s speed=0.642x
[h264 @ 0000000002918c40] concealing 1186 DC, 1186 AC, 1186 MV errors in I frame
[h264 @ 0000000002b14660] error while decoding MB 58 33, bytestream 222
[h264 @ 0000000002b14660] concealing 951 DC, 951 AC, 951 MV errors in I frame
[h264 @ 0000000002b15e80] left block unavailable for requested intra4x4 mode -1
[h264 @ 0000000002b15e80] error while decoding MB 0 30, bytestream 863
[h264 @ 0000000002b15e80] concealing 1249 DC, 1249 AC, 1249 MV errors in I frame
frame= 143 fps= 25 q=-1.0 Lsize= 200kB time=00:00:05.60 bitrate= 293.2kbits/s speed=0.994x
video:198kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.268034%
[libx264 @ 0000000002a42080] frame I:1 Avg QP:14.64 size: 31429
[libx264 @ 0000000002a42080] frame P:36 Avg QP:16.42 size: 3690
[libx264 @ 0000000002a42080] frame B:106 Avg QP:18.41 size: 356
[libx264 @ 0000000002a42080] consecutive B-frames: 0.7% 1.4% 0.0% 97.9%
[libx264 @ 0000000002a42080] mb I I16..4: 33.7% 58.7% 7.6%
[libx264 @ 0000000002a42080] mb P I16..4: 0.4% 1.0% 0.2% P16..4: 6.0% 2.2% 1.5% 0.0% 0.0% skip:88.7%
[libx264 @ 0000000002a42080] mb B I16..4: 0.0% 0.0% 0.0% B16..8: 4.3% 0.0% 0.0% direct: 0.0% skip:95.7% L0:34.4% L1:65.5% BI: 0.1%
[libx264 @ 0000000002a42080] 8x8 transform intra:59.7% inter:83.8%
[libx264 @ 0000000002a42080] coded y,uvDC,uvAC intra: 34.4% 17.3% 7.8% inter: 0.6% 0.6% 0.0%
[libx264 @ 0000000002a42080] i16 v,h,dc,p: 71% 17% 3% 10%
[libx264 @ 0000000002a42080] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 47% 22% 15% 2% 3% 3% 3% 2% 2%
[libx264 @ 0000000002a42080] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 47% 27% 11% 2% 4% 4% 3% 2% 1%
[libx264 @ 0000000002a42080] i8c dc,h,v,p: 60% 24% 15% 1%
[libx264 @ 0000000002a42080] Weighted P-Frames: Y:0.0% UV:0.0%
[libx264 @ 0000000002a42080] ref P L0: 84.6% 2.6% 10.6% 2.2%
[libx264 @ 0000000002a42080] ref B L0: 58.1% 41.5% 0.5%
[libx264 @ 0000000002a42080] ref B L1: 95.8% 4.2%
[libx264 @ 0000000002a42080] kb/s:282.50