Bug-Report: VLC 3.0.16 corrupts converted videos (black screen at start)

[CO_Windler]

The default VLC 3.0.9 of Linux Mint 20.1 has a bug that makes it lockup when closing its window ("x" button) while a video is playing. (Tested in KDE5 Plasma on AMD 2400G with recent amdgpu driver 21.20.) So you always need to enter "killall -9 vlc" to make VLC start again.

So I tried to install VLC 3.0.16 from the savoury1 PPA which indeed fixes this problem but caused much worse trouble. Particularly it corrupts converted videos, showing the first 8 seconds as black screen during playback.

https://launchpad.net/~savoury1/+archive/ubuntu/vlc3

First the requested ppa:savoury1/ffmpeg4 installs a defective version of ffmpeg 4.4 that crashes, which made e.g. youtube-dl, mkv and Celluloid unusable, showing an error. It was someting like "ffmpeg: symbol lookup error: /lib/x86_64-linux-gnu/libavcodec.so.58: undefined symbol: drmModeGetFB2". Updating to a recent kernel 5.4.80 and amdgpu version 21.20 did not help, so I removed the PPA and downgraded with aptitude ffmpeg to the previous version which runs well.

VLC 3.0.16 does not crash by closing window anymore, but has a severe bug that corrupts converted videos. Playing them in VLC (also in older version) makes the screen stay black during the first about 8 seconds (playing only audio). Only after this the window size adapts to the now visible video, which makes me conclude that VLC fails to recognize the neccesary video codec type. Setting video cache to huge 8000ms displays a still picture instead of black, which isn't useful either. The converted videos do play correctly in Celluloid and mkv those seem to be immune against the video file corruption.

The conversion bug does not appear so long x264 conversion quality is set "ultrafast" (the default, which looks extremely ugly) or at high bitrates. Also X264 profile & level set to "baseline" instead of "high" works but produces even worse pixelated video. (The selected audio resolution doesn't matter.)

I normally only use quality "slow" and convert downloaded youtube videos to fairly low resolutions (360p, 240p, sometimes 144p with video bitrates about 80..160kb/s) to save disk space. Old converted video files still play fine in VLC 3.0.16, which proves that the conversion and not playback went faulty. The bug does not appear at high bitrates, which may be the reason why it stayed undetected.

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running vlc -v outputs this: >>> co_windler@Juchhe:/usr/src$ vlc -v VLC media player 3.0.16 Vetinari (revision 3.0.13-8-g41878ff4f2) [000055f3295cc670] main libvlc: VLC wird mit dem Standard-Interface ausgeführt. Benutzen Sie 'cvlc', um VLC ohne Interface zu verwenden. Invalid Context= "Apps" line for icon theme: "/home/co_windler/.local/share/icons/Windows Vista/apps/16/" [...] Icon theme "Papirus" not found. [000055f32965d350] main playlist: playlist is empty <<< Dragging a converted video into it: >>> [000055ad63f20350] main playlist: playlist is empty [00007fee0cc01e40] mp4 stream warning: unknown box type cenc (incompletely loaded) [00007fee0c0011c0] mp4 demux warning: elst box found [00007fee0c0011c0] mp4 demux warning: STTS table of 5544 entries [00007fee0c0011c0] mp4 demux warning: elst box found [00007fee0c0011c0] mp4 demux warning: STTS table of 14111 entries [00007fee0c0011c0] mp4 demux warning: CTTS table of 20613 entries [00007fee0d56f150] faad decoder warning: decoded zero sample uint DBusMenuExporterDBus::GetLayout(int, int, const QStringList&, DBusMenuLayoutItem&): Condition failed: menu uint DBusMenuExporterDBus::GetLayout(int, int, const QStringList&, DBusMenuLayoutItem&): Condition failed: menu uint DBusMenuExporterDBus::GetLayout(int, int, const QStringList&, DBusMenuLayoutItem&): Condition failed: menu [00007fee0d57c6b0] main decoder error: buffer deadlock prevented <<< after about 8s black delay: >>> [000055ad63f6a0d0] pulse audio output warning: starting late (-14188 us) [00007fedfc006500] gl gl: Initialized libplacebo v2.72.0 (API v72) libva info: VA-API version 1.12.0 libva info: Trying to open /usr/lib/x86_64-linux-gnu/dri/radeonsi_drv_video.so libva info: Found init function __vaDriverInit_1_7 libva info: va_openDriver() returns 0 [00007feda401b520] gl gl: Initialized libplacebo v2.72.0 (API v72) [00007fee0d57c6b0] avcodec decoder: Using G3DVL VDPAU Driver Shared Library version 1.0 for hardware decoding <<< The message window outputs these warnings when video starts: >>> qt warning: orphaned video window mp4 warning: unknown box type cenc (incompletely loaded) mp4 warning: elst box found mp4 warning: STTS table of 5544 entries mp4 warning: elst box found mp4 warning: STTS table of 14111 entries mp4 warning: CTTS table of 20613 entries faad warning: decoded zero sample main error: buffer deadlock prevented <<< picture starts here: >>> pulse warning: starting late (-13563 us) gl info: Initialized libplacebo v2.72.0 (API v72) gl info: Initialized libplacebo v2.72.0 (API v72) avcodec info: Using G3DVL VDPAU Driver Shared Library version 1.0 for hardware decoding <<<

The line "[00007fee0d57c6b0] main decoder error: buffer deadlock prevented" stands for a timeout, which may have to do with failing to recognize the correct codec type during the initial 8 seconds.

The video player "mpv" uses the hardware decoder vaapi, which plays converted videos correctly. But VLC outputs green pixel garbage when trying to convert with the same(?) input codec "VA-API".

I spent a whole night trying out different VLC settings without success, so finally I could do nothing but removing the PPA and then downgrading VLC to the default version 3.0.9 through aptitude.

sudo add-apt-repository -r ppa:savoury1/vlc3

[CO_Windler]

The default VLC 3.0.9 converts correctly, but VLC always had the issue that the first seconds of converted video look blocky (also on Windows). I conclude that the 1st I- frame (keyframe) at the begin of each converted video has too low resolution and in 3.0.16 gets additionally damaged or even is missing. I suspect that VLC treats everything as streaming, and hence even in a files will not try to search forward to collect more data, which makes its video playback more vulnerable against this type of bug than other players.

I have now returned to VLC 3.0.9 because I need video conversion. I use VLC mainly for playing downloaded video files and converting them to lower resolutions. I do not need the streaming features.

As a collector and hardware researcher of music keyboards and soundtoys, for reference I keep on my harddisk tons of downloaded youtube tech info and tutorial videos. Hence I need VLC for quick sighting and conversion (file size reduction). Yet I used this this on my main PC (Colani bigtower), but because the highend Win98SE machine (AMD K6-3@550MHz, 768MB RAM) became completely overloaded with this work (160GB harddrive full to the brim and FAT32 too slow), I installed an additional modern ITX mainboard with AMD 2400G, 16GB RAM and 8TB harddrive running Linux Mint. Additionally I have an older VLC installed on my IBM Thinkpad X61t laptop (Intel Core2Duo 1.6GHz with Intel graphics, 4GB RAM, 160GB HDD, wifi removed, running an old Win10 version).

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MAY THE SOFTWARE BE WITH YOU! *============================================================================* I CYBERYOGI Christian Oliver(=CO=) Windler I I (teachmaster of LOGOLOGIE - the first cyberage-religion!) I I ! I *=============================ABANDON=THE=BRUTALITY==========================*

[Rémi Denis-Courmont]

You messed up your install by using the PPA, is all.

[CO_Windler]

Using a PPA can not "mess up the install" when it does actually run. ("File not found" would be the result of a wrong Linux brand or version.) It might be some kind of MESA or amdgpu driver incompatibility, but I had tried all kinds of different modes (also software renderer) which always caused the roughly first 8 seconds of a converted video becoming black screen.

I typically use these conversion parameters:

Encapsulation: MP4/MOV
Video Codec: H-264 (with custom bitrate and height set)
Audio Codec: MP3 (44100 Hz, custom bitrate)

Sometimes I keep video or audio as original stream, but once the video stream got modified (lower bitrate and/or height), the start of the converted video became black when played in VLC. I had initially kept one of those misconverted video files (now deleted) which also remained for 8s black after reinstalling VLC 3.0.9, thus definitely the converted files were somehow faulty (first I-frame missing?) despite they were playable on Celluloid or mkv (which automatically searches for the next I-frame when the 1st is faulty/absent?).