问题描述
当我们使用HEVC + RTSP时，ffmpeg可以正常工作。该流由网络摄像头捕获。
ffmpeg -f dshow -rtbufsize 100M -f vfwcap -i "0" -strict experimental -c:v hevc_qsv -f rtsp -rtsp_transport tcp rtsp://127.0.0.1/live/test
输出类似于：
frame= 355 fps= 37 q=-0.0 size=N/A time=00:00:11.27 bitrate=N/A dup=159 drop=0 speed=1.18x
然后我们切换到VP9 + RTSP。
ffmpeg -f dshow -rtbufsize 100M -f vfwcap -i "0" -strict experimental -c:v libvpx-vp9 -f rtsp -rtsp_transport tcp rtsp://127.0.0.1/live/test
fps和速度看起来太慢：
frame= 263 fps=9.5 q=0.0 size=N/A time=00:00:07.94 bitrate=N/A dup=119 drop=0 speed=0.288x
然后，我们使用ffplay播放流。有很多错误消息，视频似乎被冻结。
[vp9 @ 000001c3da86c200] Not all references are available
[vp9 @ 000001c3dffd5700] Not all references are available
[vp9 @ 000001c3da8477c0] Not all references are available
[vp9 @ 000001c3da848240] Not all references are available
[vp9 @ 000001c3da848e40] Not all references are available
[vp9 @ 000001c3e01d2fc0] Not all references are available
[vp9 @ 000001c3e01dd280] Not all references are available
[vp9 @ 000001c3e01e8980] Not all references are available
[vp9 @ 000001c3e01f1880] Not all references are available
[vp9 @ 000001c3da86c200] Not all references are available
[vp9 @ 000001c3dffd5700] Not all references are available
[vp9 @ 000001c3da8477c0] Not all references are available
[vp9 @ 000001c3da848240] Not all references are available
[vp9 @ 000001c3da848e40] Not all references are available
[vp9 @ 000001c3e01d2fc0] Not all references are available
[vp9 @ 000001c3e01dd280] Not all references are available0B f=0/0
[vp9 @ 000001c3e01e8980] Not all references are available
[vp9 @ 000001c3e01f1880] Not all references are available
[vp9 @ 000001c3da86c200] Not all references are available
[vp9 @ 000001c3dffd5700] Not all references are available
[vp9 @ 000001c3da8477c0] Not all references are available
[vp9 @ 000001c3da848240] Not all references are available
[vp9 @ 000001c3da848e40] Not all references are available
[vp9 @ 000001c3e01d2fc0] Not all references are available
[vp9 @ 000001c3e01dd280] Not all references are available
[vp9 @ 000001c3e01e8980] Not all references are available
[vp9 @ 000001c3e01f1880] Not all references are available
最后，我们尝试硬件VP9编码器。
ffmpeg -f dshow -rtbufsize 100M -f vfwcap -i "0" -strict experimental -c:v vp9_qsv -f rtsp -rtsp_transport tcp rtsp://127.0.0.1/live/test
它不起作用。
[swscaler @ 0000021e88df9fc0] deprecated pixel format used,make sure you did set range correctly
[vp9_qsv @ 0000021e8687df80] Selected ratecontrol mode is unsupported
[vp9_qsv @ 0000021e8687df80] Low power mode is unsupported
[vp9_qsv @ 0000021e8687df80] Current frame rate is unsupported
[vp9_qsv @ 0000021e8687df80] Current picture structure is unsupported
[vp9_qsv @ 0000021e8687df80] Current resolution is unsupported
[vp9_qsv @ 0000021e8687df80] Current pixel format is unsupported
[vp9_qsv @ 0000021e8687df80] some encoding parameters are not supported by the QSV runtime. Please double check the input parameters.
Error initializing output stream 0:0 -- Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate,rate,width or height
Conversion Failed!
那么，如何才能成功处理VP9 + RTSP？
解决方法
我绝不是这方面的权威，但我的情况与您相似。如果我理解 this GitHub issue correctly，“第 9 代”英特尔 GPU——“Kaby Lake、Coffee Lake、Whiskey Lake、Comet Lake”per Wikipedia，我认为它对应于 7xxx 到 10xxx——具有硬件支持VP9 编码，但 Windows 驱动程序不公开此功能供媒体 SDK 使用。我认为我们看到的错误消息反映了 QSV 编码在我们的特定 CPU 模型和操作系统上不可用的事实。
出于某种原因，该功能在 Linux 上可用。我看到几个消息来源说 VA API (vp9_vaapi) 应该适用于这些“第 9 代”处理器中的任何一个； QSV 驱动程序 (vp9_qsv) 可能也适用于 Linux。我还没有机会尝试。