video2x Failed to initialize encoder: Function not implemented

Hi, I face problems while trying to process videos with Video2X Qt6 6.4.0

Describe the bug The program fails to process video files, returning an error message: "Video processing finished with errors. See logs for more information.

To Reproduce Steps to reproduce the behavior:

Open Video2X Qt6 6.4.0.
Add a video file for processing ( anyvideo.mp4).
Select the Real-ESRGAN processor and start the task.
Observe the task failure with an error message.

Expected behavior The video file should process successfully without errors, and the upscaled output file should be generated.

Actual behavior The task fails with the following error in the logs: [2025-06-13 11:36:03] [info] Initializing Video2X Qt6 6.4.0 [2025-06-13 11:36:03] [info] Checking for available updates... [2025-06-13 11:36:04] [info] No upgrades available. [2025-06-13 11:36:32] [warning] File 'E:/Montage/Nouveau dossier/S01E01 - Mermaid Forest- Une sirène ne sourit jamais(VOST).realesrgan.mkv' already exists, finding a new name [2025-06-13 11:36:32] [warning] Writing output file to 'E:/Montage/Nouveau dossier/S01E01 - Mermaid Forest- Une sirène ne sourit jamais(VOST).realesrgan.1.mkv' [2025-06-13 11:36:32] [info] [FFmpeg] [libx264 @ 00000234cb2fcac0] using SAR=1/1 [2025-06-13 11:36:32] [info] [FFmpeg] [libx264 @ 00000234cb2fcac0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2 AVX512 [2025-06-13 11:36:32] [info] [FFmpeg] [libx264 @ 00000234cb2fcac0] profile High, level 5.0, 4:2:0, 8-bit [2025-06-13 11:36:32] [info] [FFmpeg] [libx264 @ 00000234cb2fcac0] 264 - core 164 r3192 c24e06c - H.264/MPEG-4 AVC codec - Copyleft 2003-2024 - http://www.videolan.org/x264.html - options: cabac=1 ref=5 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=8 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=2 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=24 lookahead_threads=4 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=3 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=50 rc=crf mbtree=1 crf=20.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00 [2025-06-13 11:36:32] [error] [FFmpeg] [matroska @ 00000234ccbb0cc0] Subtitle codec 94213 is not supported. [2025-06-13 11:36:32] [error] Error writing output file header [2025-06-13 11:36:32] [critical] Failed to initialize encoder: Function not implemented

Environment:

OS: Windows 10 24H2
GPU: AMD 780m iGPU (AMD Ryzen 9 7940HS)
Video2X Qt Version: 6.4.0

Jun 13 '25 10:06 chp-1960

I have encountered this exact issues when trying to process a clip I got from a DJI Mini drone. The issue is with the format of the embedded subtitle (the drone adds some metadata such as capture settings, gps position and velocity data). If I use ffmpeg to strip the subtitle, it works correctly. This is what I get if I run ffprobe on the file

Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '.\test.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    creation_time   : 2023-01-14T11:31:54.000000Z
    encoder         : Lavf59.27.100
    comment         : DE=None,SN=1SFOHCH0AB0XY5, Type=Normal, HQ=Normal, Mode=P
    location-{    : +45.5501+025.2656/
    location        : +45.5501+025.2656/
  Duration: 00:00:05.00, start: 0.000000, bitrate: 32210 kb/s
  Stream #0:0[0x1](eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709, progressive), 2720x1530 [SAR 1:1 DAR 16:9], 40215 kb/s, 29.97 fps, 29.97 tbr, 30k tbn (default)
      Metadata:
        creation_time   : 2023-01-14T11:31:54.000000Z
        handler_name    : ?DJI.AVC
        vendor_id       : [0][0][0][0]
        encoder         : AVC encoder
  Stream #0:1[0x2](eng): Subtitle: mov_text (tx3g / 0x67337874), 2 kb/s (default)
      Metadata:
        creation_time   : 2023-01-14T11:31:54.000000Z
        handler_name    : ?DJI.Subtitle

The fix would probably be as simple as using -c:s copy when an unknown subtitle stream is found

Jul 25 '25 04:07 alexkiri

I'm having the same issue:

[2025-09-01 19:13:27] [warning] Skipping unsupported stream type at index: 3 [2025-09-01 19:13:27] [error] [FFmpeg] [matroska @ 0000024f9fcc6c40] Subtitle codec 94213 is not supported. [2025-09-01 19:13:27] [error] Error writing output file header [2025-09-01 19:13:27] [critical] Failed to initialize encoder: Function not implemented

Thanks!

Sep 02 '25 00:09 ceinstaller