[mkv] Discarding potentially broken or useless index.

[Blues]

Avidemux from GIT, built today. When I encode using H.265 the resulting file is not seekable. The error MKV player is giving me is in subject. The file plays, audio is fine, but picture is frozen. I loaded the file back into Avidemux and it exhibits the same problem.
What's the problem?

[Jan Gruuthuse]

Your hardware does support h.265? and the used profile? could be hardware or driver limitation?
Does VLC play the video?

[Blues]

Yes, my hardware supports 8-bit H.265, other [older] files play fine. MPV is using VAAPI hardware decoding, plays fine, freezes when seeking. VLC behaves exactly the same. It starts playing, but I cannot seek forward, the picture freezes.

Code Select Expand

Video
ID                                       : 1
Format                                   : HEVC
Format/Info                              : High Efficiency Video Coding
Format profile                           : Main@L3@Main
Codec ID                                 : V_MPEGH/ISO/HEVC
Duration                                 : 1 h 42 min
Bit rate                                 : 624 kb/s
Width                                    : 640 pixels
Height                                   : 476 pixels
Display aspect ratio                     : 4:3
Frame rate mode                          : Constant
Frame rate                               : 25.000 FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Bits/(Pixel*Frame)                       : 0.082
Stream size                              : 459 MiB (76%)
Writing library                          : x265 2.5:[Linux][GCC 7.1.0][64 bit] 8bit+10bit+12bit
Encoding settings                        : cpuid=1173503 / frame-threads=2 / wpp / no-pmode / no-pme / no-psnr / no-ssim / log-level=2 / input-csp=1 / input-res=640x476 / interlace=0 / total-frames=0 / level-idc=0 / high-tier=1 / uhd-bd=0 / ref=3 / no-allow-non-conformance / no-repeat-headers / annexb / no-aud / no-hrd / info / hash=0 / no-temporal-layers / open-gop / min-keyint=25 / keyint=250 / bframes=3 / b-adapt=1 / b-pyramid / bframe-bias=0 / rc-lookahead=40 / lookahead-slices=0 / scenecut=40 / no-intra-refresh / ctu=64 / min-cu-size=8 / no-rect / no-amp / max-tu-size=32 / tu-inter-depth=1 / tu-intra-depth=1 / limit-tu=0 / rdoq-level=0 / dynamic-rd=0.00 / no-ssim-rd / signhide / no-tskip / nr-intra=0 / nr-inter=0 / no-constrained-intra / strong-intra-smoothing / max-merge=2 / limit-refs=3 / no-limit-modes / me=3 / subme=5 / merange=16 / temporal-mvp / weightp / weightb / no-analyze-src-pics / deblock=0:0 / sao / no-sao-non-deblock / rd=3 / early-skip / rskip / no-fast-intra / no-tskip-fast / no-cu-lossless / no-b-intra / rdpenalty=0 / psy-rd=1.00 / psy-rdoq=0.00 / no-rd-refine / analysis-reuse-mode=0 / no-lossless / cbqpoffs=0 / crqpoffs=0 / rc=crf / crf=23.0 / qcomp=0.60 / qpstep=4 / stats-write=0 / stats-read=0 / ipratio=1.40 / pbratio=1.30 / aq-mode=2 / aq-strength=1.00 / cutree / zone-count=0 / no-strict-cbr / qg-size=32 / no-rc-grain / qpmax=69 / qpmin=0 / no-const-vbv / sar=0 / overscan=0 / videoformat=5 / range=0 / colorprim=2 / transfer=2 / colormatrix=2 / chromaloc=0 / display-window=0 / max-cll=0,0 / min-luma=0 / max-luma=255 / log2-max-poc-lsb=8 / vui-timing-info / vui-hrd-info / slices=1 / opt-qp-pps / opt-ref-list-length-pps / no-multi-pass-opt-rps / scenecut-bias=0.05 / no-opt-cu-delta-qp / no-aq-motion / no-hdr / no-hdr-opt / no-dhdr10-opt / analysis-reuse-level=5 / scale-factor=0 / refine-intra=0 / refine-inter=0 / refine-mv=0 / no-limit-sao / ctu-info=0
Default                                  : Yes
Forced                                   : No

[eumagga0x2a]

I tried encoding a short (8 min) video using the x265 encoder with the "superfast" preset, main profile, no tuning and the MKV muxer: the resulting video is perfectly seekable in Avidemux and in mpv with software decoding (my hardware doesn't offer accelerated h265 decoding). Please specify exact steps to reproduce and provide a sample.

[Blues]

Sample. I used all default settings with H.265 except setting quality to 23. I can provide a longer sample if needed, I used dd to cut a piece from beginning.

[Jan Gruuthuse]

Your mkv h.265 sample does play in vlc 3.0.0 Vetinari. It does not allow moving in the timeline.

Simple workaround for now: Remux with mkv toolnix: https://mkvtoolnix.download/
Remuxed mkv: https://we.tl/yIYQmC8iW6
Until developers tackle the issue, time permitting.

[eumagga0x2a]

I used all default settings with H.265 except setting quality to 23.

Can't reproduce with the settings specified. The resulting MKV from the same source as above is again perfectly seekable.

Avidemux built on Fedora 26 from the current git with x265 v2.4 from RPF Fusion.

(The provided sample is indeed broken.)

[Blues]

My apologies. Now I recall I used filters, GreyScale and probably a noise filter, can't remember. Will try and do it again, this time I'll take a note of filters used.

[eumagga0x2a]

Filters, at least those which don't manipulate timing, shouldn't matter. The x265 version might matter, the source might matter.

[Blues]

Yes, I can reproduce a broken file without filters. So where I should look? Handbrake output does not suffer from this issue. My x265 version is 2.5.

[eumagga0x2a]

The x265 version is the key. I can confirm the issue with 2.5, works fine with 2.4.

[Blues]

Thanks for confirmation. Will wait, hope it gets fixed.

[eumagga0x2a]

I'd rather downgrade x265 for now.

[Blues]

Hmmm ... can I bundle older x265 instead of using system x265?

[eumagga0x2a]

You will have to build Avidemux against the older version in the first place.