How to use hevc_cuvid decoder to convert a yuvj420p format mov file into h264 mp4

Gaming and Visualization Technologies Video Codec, PyNv & OFA
1

solved : using cuda for hwaccel option

I have a video.mov, codec hvc1, pix fmt yuvj420p. And I tried to transcode it into mp4(h264) by ffmpeg with hwaccel

My command is

ffmpeg -y -hwaccel cuvid -c:v hevc_cuvid -i hevc.mov -c:v h264_nvenc output.mp4

But I got error

Impossible to convert between the formats supported by the filter 'graph 0 input from stream 0:0' 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

Below is my information

Metadata:
    major_brand     : qt
    minor_version   : 0
    compatible_brands: qt
    creation_time   : 2021-07-14T09:05:40.000000Z
    com.apple.quicktime.location.accuracy.horizontal: 65.000000
    com.apple.quicktime.location.ISO6709: +24.9560+121.2247+144.619/
    com.apple.quicktime.make: Apple
    com.apple.quicktime.model: iPhone X
    com.apple.quicktime.software: 14.6
    com.apple.quicktime.creationdate: 2021-07-14T17:05:04+0800
  Duration: 00:00:17.95, start: 0.000000, bitrate: 22770 kb/s
    Stream #0:0(und): Video: hevc (Main) (hvc1 / 0x31637668), yuvj420p(pc, bt709), 3840x2160, 22603 kb/s, 59.99 fps, 60 tbr, 600 tbn, 600 tbc (default)
    Metadata:
      rotate          : 90
      creation_time   : 2021-07-14T09:05:40.000000Z
      handler_name    : Core Media Video
      encoder         : HEVC
    Side data:
      displaymatrix: rotation of -90.00 degrees
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 86 kb/s (default)
    Metadata:
      creation_time   : 2021-07-14T09:05:40.000000Z
      handler_name    : Core Media Audio
    Stream #0:2(und): Data: none (mebx / 0x7862656D), 0 kb/s (default)
    Metadata:
      creation_time   : 2021-07-14T09:05:40.000000Z
      handler_name    : Core Media Metadata
    Stream #0:3(und): Data: none (mebx / 0x7862656D), 0 kb/s (default)
    Metadata:
      creation_time   : 2021-07-14T09:05:40.000000Z
      handler_name    : Core Media Metadata
    Stream #0:4(und): Data: none (mebx / 0x7862656D), 69 kb/s (default)
    Metadata:
      creation_time   : 2021-07-14T09:05:40.000000Z
      handler_name    : Core Media Metadata

NAME="Ubuntu"
VERSION="18.04.5 LTS (Bionic Beaver)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 18.04.5 LTS"
VERSION_ID="18.04"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=bionic
UBUNTU_CODENAME=bionic

nvidia-smi
Thu Jul 15 14:47:40 2021
+-----------------------------------------------------------------------------+
| NVIDIA-SMI 450.51.06    Driver Version: 450.51.06    CUDA Version: 11.0     |
|-------------------------------+----------------------+----------------------+
| GPU  Name        Persistence-M| Bus-Id        Disp.A | Volatile Uncorr. ECC |
| Fan  Temp  Perf  Pwr:Usage/Cap|         Memory-Usage | GPU-Util  Compute M. |
|                               |                      |               MIG M. |
|===============================+======================+======================|
|   0  Tesla T4            Off  | 00000000:00:04.0 Off |                    0 |
| N/A   33C    P8     9W /  70W |      0MiB / 15109MiB |      0%      Default |
|                               |                      |                  N/A |
+-------------------------------+----------------------+----------------------+

+-----------------------------------------------------------------------------+
| Processes:                                                                  |
|  GPU   GI   CI        PID   Type   Process name                  GPU Memory |
|        ID   ID                                                   Usage      |
|=============================================================================|
|  No running processes found                                                 |
+-----------------------------------------------------------------------------+
2

Try to remove -hwaccel option. You don’t need it with NVDEC/NVENC. The conversion from yuvj420P to yuv420P has to be done by pure CPU-based libswscale internally.

3

This is false. Though you can use more modern -hwaccel cuda hwaccel_output_format cuda.

And there is no need to use swscale either.