我正在尝试为视频添加时间戳。
我使用 drawtext 与 pts 和 gmtime 来实现它。
但是，当我尝试使用VAAPI来加速进度时，出现了错误。
这是我的 ffmpeg 命令：
ffmpeg \
-hwaccel vaapi -hwaccel_device /dev/dri/renderD128 \
-i input.mp4 \
-vf "drawtext=fontfile='/usr/share/fonts/truetype/msttcorefonts/arial.ttf': \
[email protected]: fontsize=50: x=60: y=1000: \
text='%{pts\:gmtime\:$(/bin/date -d "20200101 10:30:00" +"%s")\:%Y-%m-%d %T}', \
format=nv12|vaapi,hwupload,hwdownload" \
-b:v 10M -c:a copy -vcodec h264_vaapi \
-y output.mp4
它返回：
[hwupload @ 0x55d7727a4bc0] A hardware device reference is required to upload frames to.
[Parsed_hwupload_2 @ 0x55d7727a4ac0] Query format failed for 'Parsed_hwupload_2': Invalid argument
Error reinitializing filters!
Failed to inject frame into filter network: Invalid argument
Error while processing the decoded data for stream #0:0
Conversion failed!
如果我删除 hwupload，我会得到：
Impossible to convert between the formats supported by the filter 'Parsed_format_1' and the filter 'auto_scaler_0'
Error reinitializing filters!
Failed to inject frame into filter network: Function not implemented
Error while processing the decoded data for stream #0:0
Conversion failed!
有人能帮忙指出我遗漏了什么或者命令错误的地方吗？
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更新：@Gyan 指出我应该hwdownload在 之前插入drawtext。我按照他的建议，没有硬件编码，ffmpeg 开始工作。我尝试启用硬件编码，但再次出现错误。这是我修改后的命令：
ffmpeg \
-hwaccel vaapi -hwaccel_device /dev/dri/renderD128 \
-i input.mp4 \
-vf "format=nv12|vaapi,hwdownload, \
drawtext=fontfile='/usr/share/fonts/truetype/msttcorefonts/arial.ttf': \
[email protected]: fontsize=50: x=60: y=1000: \
text='%{pts\:gmtime\:$(/bin/date -d "20200101 10:30:00" +"%s")\:%Y-%m-%d %T}', \
format=nv12|vaapi,hwupload" \
-b:v 10M -c:a copy -vcodec h264_vaapi \
-y output.mp4
错误信息如下：
[hwupload @ 0x557b78829880] A hardware device reference is required to upload frames to.
[Parsed_hwupload_4 @ 0x557b78839500] Query format failed for 'Parsed_hwupload_4': Invalid argument
Error reinitializing filters!
Failed to inject frame into filter network: Invalid argument
Error while processing the decoded data for stream #0:0
Conversion failed!
有人能帮忙再检查一下命令吗？或者 drawtext 不能与硬件编码一起使用吗？