前提：在 windows/linux 上，使用同样一个 ffmpeg 静态编译的可执行文件，对同样一个 h264 编码的 mp4 文件解码，解码命令如下： (1) .\ffmpeg.exe -hwaccel cuda -i E:\tmp\1080p_60_10M.mp4 -f null - 解码帧率为 fps=780 (2) .\ffmpeg.exe -i E:\tmp\1080p_60_10M.mp4 -f null - 解码帧率为 fps=1617

(1) 解码结果:

  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'E:\tmp\1080p_60_10M.mp4':

Metadata: major_brand : isom minor_version : 512 compatible_brands: isomiso2avc1mp41 encoder : Lavf60.3.100 Duration: 00:01:36.67, start: 0.000000, bitrate: 10533 kb/s Stream #0:00x1: Video: h264 (High) (avc1 / 0x31637661), yuv420p(progressive), 1920x1080 [SAR 1:1 DAR 16:9], 10528 kb/s, 60 fps, 60 tbr, 15360 tbn (default) Metadata: handler_name : VideoHandler vendor_id : [0][0][0][0] encoder : Lavc60.3.100 libx264 Stream mapping: Stream #0:0 -> #0:0 (h264 (native) -> wrapped_avframe (native)) Press [q] to stop, [?] for help Output #0, null, to 'pipe:': Metadata: major_brand : isom minor_version : 512 compatible_brands: isomiso2avc1mp41 encoder : Lavf60.22.101 Stream #0:0(und): Video: wrapped_avframe, nv12(progressive), 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 60 fps, 60 tbn (default) Metadata: handler_name : VideoHandler vendor_id : [0][0][0][0] encoder : Lavc60.40.100 wrapped_avframe [out#0/null @ 0000017e54639b80] video:2719KiB audio:0KiB subtitle:0KiB other streams:0KiB global headers:0KiB muxing overhead: unknown frame= 5800 fps=780 q=-0.0 Lsize=N/A time=00:01:36.66 bitrate=N/A speed= 13x

(2) 解码结果:

    Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'E:\tmp\1080p_60_10M.mp4':

Metadata: major_brand : isom minor_version : 512 compatible_brands: isomiso2avc1mp41 encoder : Lavf60.3.100 Duration: 00:01:36.67, start: 0.000000, bitrate: 10533 kb/s Stream #0:00x1: Video: h264 (High) (avc1 / 0x31637661), yuv420p(progressive), 1920x1080 [SAR 1:1 DAR 16:9], 10528 kb/s, 60 fps, 60 tbr, 15360 tbn (default) Metadata: handler_name : VideoHandler vendor_id : [0][0][0][0] encoder : Lavc60.3.100 libx264 Stream mapping: Stream #0:0 -> #0:0 (h264 (native) -> wrapped_avframe (native)) Press [q] to stop, [?] for help Output #0, null, to 'pipe:': Metadata: major_brand : isom minor_version : 512 compatible_brands: isomiso2avc1mp41 encoder : Lavf60.22.101 Stream #0:0(und): Video: wrapped_avframe, yuv420p(progressive), 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 60 fps, 60 tbn (default) Metadata: handler_name : VideoHandler vendor_id : [0][0][0][0] encoder : Lavc60.40.100 wrapped_avframe [out#0/null @ 000001f2b2f29c00] video:2719KiB audio:0KiB subtitle:0KiB other streams:0KiB global headers:0KiB muxing overhead: unknown frame= 5800 fps=1617 q=-0.0 Lsize=N/A time=00:01:36.66 bitrate=N/A speed=26.9x

问题：指定了 -hwaccel cuda 参数进行解码的 fps 要比不指定这个参数进行解码的帧率少了一倍，自己的主机是 nvidia 显卡，这个可能是什么原因？