error compiling ffmpeg on a T4

[ghost]

HI! It seems to me than on my kernel 5.7.2 I have all the requirements meet to enable the VPU acceleration.

pi@arm-64:/media/pi/DATOS/pbp-tools$ vainfo libva info: VA-API version 1.8.0 libva info: User environment variable requested driver 'v4l2_request' libva info: Trying to open /usr/local/lib/aarch64-linux-gnu/dri/v4l2_request_drv_video.so libva info: Found init function __vaDriverInit_1_8 libva info: va_openDriver() returns 0 vainfo: VA-API version: 1.8 (libva 2.8.0.1) vainfo: Driver version: v4l2-request vainfo: Supported profile and entrypoints VAProfileMPEG2Simple : VAEntrypointVLD VAProfileMPEG2Main : VAEntrypointVLD VAProfileH264Main : VAEntrypointVLD VAProfileH264High : VAEntrypointVLD VAProfileH264ConstrainedBaseline: VAEntrypointVLD VAProfileH264MultiviewHigh : VAEntrypointVLD VAProfileH264StereoHigh : VAEntrypointVLD

but I fail on compiling ffmpeg

In function ‘strncpy’,
    inlined from ‘ff_v4l2_m2m_codec_init’ at libavcodec/v4l2_m2m.c:362:9:
/usr/include/aarch64-linux-gnu/bits/string_fortified.h:106:10: warning: ‘__builtin___strncpy_chk’ specified bound depends on the length of the source argument [-Wstringop-overflow=]
  106 |   return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest));
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
libavcodec/v4l2_m2m.c: In function ‘ff_v4l2_m2m_codec_init’:
libavcodec/v4l2_m2m.c:362:35: note: length computed here
  362 |         strncpy(s->devname, node, strlen(node) + 1);
      |                                   ^~~~~~~~~~~~
CC  libavcodec/v4l2_m2m_enc.o
CC  libavcodec/v4l2_request.o
CC  libavcodec/v4l2_request_h264.o
libavcodec/v4l2_request.c: In function ‘v4l2_request_queue_decode’:
libavcodec/v4l2_request.c:294:90: error: ‘V4L2_BUF_FLAG_M2M_HOLD_CAPTURE_BUF’ undeclared (first use in this function)
  294 |     ret = v4l2_request_queue_buffer(ctx, req->request_fd, &req->output, last_slice ? 0 : V4L2_BUF_FLAG_M2M_HOLD_CAPTURE_BUF);
      |                                                                                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
libavcodec/v4l2_request.c:294:90: note: each undeclared identifier is reported only once for each function it appears in
CC  libavcodec/v4l2_request_hevc.o
libavcodec/v4l2_request.c: In function ‘ff_v4l2_request_decode_slice’:
libavcodec/v4l2_request.c:378:37: error: ‘V4L2_BUF_CAP_SUPPORTS_M2M_HOLD_CAPTURE_BUF’ undeclared (first use in this function)
  378 |     if ((req->output.capabilities & V4L2_BUF_CAP_SUPPORTS_M2M_HOLD_CAPTURE_BUF) != V4L2_BUF_CAP_SUPPORTS_M2M_HOLD_CAPTURE_BUF)
      |                                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
libavcodec/v4l2_request.c: In function ‘ff_v4l2_request_output_frame’:
libavcodec/v4l2_request.c:391:25: warning: unused variable ‘ctx’ [-Wunused-variable]
  391 |     V4L2RequestContext *ctx = avctx->internal->hwaccel_priv_data;
      |                         ^~~
make: *** [ffbuild/common.mak:59: libavcodec/v4l2_request.o] Error 1
make: *** Se espera a que terminen otras tareas....

hope you can help me here.

[xmixahlx]

you build 5.7.2 with hwaccel support? the linux kernel with hwaccel patch is required to build ffmpeg with v4l2request support. also, vaapi is NOT required to build ffmpeg.

[ghost]

Okay!! Gotcha! So the patch it's unofficial and will not be merged on mainline?

[xmixahlx]

it is currently WIP, which is why the hwaccel patch is needed.