Dear FFmpeg Development Team,
I hope this message finds you well.
We are encountering an issue when processing a video file using FFmpeg, and we
are hoping you can provide some assistance. The video in question is in MJPEG
format and features a transition from 8-bit greyscale to an YUV420 color space
at some point during playback.
Here is the issue we are experiencing:
Conversion with FFmpeg:
When we convert the video using FFmpeg, the filter graph appears to adjust
correctly to the different color spaces. The video plays correctly when
processed in forward motion, but it ends up being completely in greyscale.
Reversing the Video:
When we attempt to reverse the video using the following command:
ffmpeg -ss 380 -to 480 -i input.avi -filter_complex "[0]reverse" out4.mp4
the video file becomes corrupted. Specifically, the greyscale portions of the
video are skipped, and the non-greyscale sections are displayed in color. This
results in a fragmented output where parts of the video are missing entirely
(the greyscale segments), and other parts are displayed in color.
We are unable to share the video file due to privacy and data protection
reasons, but we have attached the relevant FFmpeg output as a .txt file for
your reference. We hope that this will help you better understand the issue.
Our request: Could you please assist us in identifying the cause of this
behavior? It seems that FFmpeg may not be properly handling the transition
between the different color spaces when reversing the video. We would
appreciate any insights or potential solutions you can provide to help us
resolve this issue.
Thank you very much for your time and assistance. We look forward to your
guidance and support.
Best regards,
Enrico Schreier
(c) ERDMANN-Softwaregesellschaft mbH
Gesch?ftsf?hrer: Ulrich Erdmann
Dr.-Kahlbaum-Allee 16
02826 G?RLITZ
DEUTSCHLAND
Telefon: +49 3581 4761-0
Telefax: +49 3581 4761-99
E-Mail: i...@erdmannsoftware.com
Rechtsform: Gesellschaft mit beschr?nkter Haftung
Handelsregister: Amtsgericht Dresden HRB 9857
ffmpeg version 7.1.1 Copyright (c) 2000-2025 the FFmpeg developers
built with Microsoft (R) C/C++-Optimierungscompiler Version 19.40.33811 f�r
x64
configuration: --prefix=../../output --toolchain=msvc --arch=x86_64
--enable-libopenh264 --extra-ldflags='-LIBPATH:../../libs'
--extra-cflags=-I../../libs
libavutil 59. 39.100 / 59. 39.100
libavcodec 61. 19.101 / 61. 19.101
libavformat 61. 7.100 / 61. 7.100
libavdevice 61. 3.100 / 61. 3.100
libavfilter 10. 4.100 / 10. 4.100
libswscale 8. 3.100 / 8. 3.100
libswresample 5. 3.100 / 5. 3.100
Input #0, avi, from '.\input.avi':
Duration: 00:10:13.40, start: 0.000000, bitrate: 14007 kb/s
Stream #0:0: Video: mjpeg (Baseline) (MJPG / 0x47504A4D), yuvj420p(pc,
bt470bg/unknown/unknown), 2048x2048 [SAR 1:1 DAR 1:1], 14010 kb/s, 5 fps, 5
tbr, 5 tbn
File 'out4.mp4' already exists. Overwrite? [y/N] y
Stream mapping:
Stream #0:0 (mjpeg) -> reverse:default
reverse:default -> Stream #0:0 (mpeg4)
Press [q] to stop, [?] for help
[fc#0 @ 000001772AF54A40] Reconfiguring filter graph because video parameters
changed to yuvj420p(pc, bt470bg), 2048x2048
[swscaler @ 000001772E71B2C0] deprecated pixel format used, make sure you did
set range correctly
Output #0, mp4, to 'out4.mp4':
Metadata:
encoder : Lavf61.7.100
Stream #0:0: Video: mpeg4 (mp4v / 0x7634706D), yuv420p(tv,
bt470bg/unknown/unknown, progressive), 2048x2048 [SAR 1:1 DAR 1:1], q=2-31, 200
kb/s, 5 fps, 10240 tbn
Metadata:
encoder : Lavc61.19.101 mpeg4
Side data:
cpb: bitrate max/min/avg: 0/0/200000 buffer size: 0 vbv_delay: N/A
[out#0/mp4 @ 000001772AF44AC0] video:21413KiB audio:0KiB subtitle:0KiB other
streams:0KiB global headers:0KiB muxing overhead: 0.015378%
frame= 500 fps= 43 q=31.0 Lsize= 21417KiB time=00:02:43.80
bitrate=1071.1kbits/s speed=14.1x_______________________________________________
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