#9054: low qsv encode performance
-------------------------------------+-------------------------------------
Reporter: dandenson | Type: defect
Status: new | Priority: normal
Component: | Version:
undetermined | unspecified
Keywords: | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
-------------------------------------+-------------------------------------
Summary of the bug:
using this command, or variations with hevc_qsv, with or without -hwaccel
qsv, video errors and segfaults and lower than expected performance.
ffmpeg -hwaccel qsv -i
http://hdhomerun:5004/auto/v2.1 -c:v hevc_qsv -c:a aac -b:a 64k
-profile:v main -global_quality 30 -g 48 -keyint_min 48 -sc_threshold
0 -hls_time 2 -hls_list_size 8 -hls_segment_type mpegts -cc_stream_map
"ccgroup:cc,instreamid:CC1,language:en" -hls_flags delete_segments
-hls_segment_filename 720p_%03d.ts 720p.m3u8
CPU is i3-10100 which is able to handle at least 14 full h.264 transcodes,
likely more. I am only able to encode 2 hevc streams and those streams
segfault frequently. If I introduce a 3rd stream, all 3 encoders struggle
and will segfault within a few minutes. They also don't produce real-time
results.
My expectation based on single file testing and other software packages is
that I should be able to handle 4 hevc encodes at 30fps using qsv, I'm
only getting 2 and those are having substantial issues.
Here is the output of ffmpeg when running the above script. This was
cancelled after the third ts file what written:
ffmpeg version 4.3.1-4ubuntu1 Copyright (c) 2000-2020 the FFmpeg
developers
built with gcc 10 (Ubuntu 10.2.0-9ubuntu2)
configuration: --prefix=/usr --extra-version=4ubuntu1
--toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu
--incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl
--disable-stripping --enable-avresample --disable-filter=resample
--enable-gnutls --enable-ladspa --enable-libaom --enable-libass
--enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio
--enable-libcodec2 --enable-libdav1d --enable-libflite
--enable-libfontconfig --enable-libfreetype --enable-libfribidi
--enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame
--enable-libmysofa --enable-libopenjpeg --enable-libopenmpt
--enable-libopus --enable-libpulse --enable-librabbitmq
--enable-librsvg --enable-librubberband --enable-libshine
--enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libsrt
--enable-libssh --enable-libtheora --enable-libtwolame
--enable-libvidstab --enable-libvorbis --enable-libvpx
--enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2
--enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2
--enable-omx --enable-openal --enable-opencl --enable-opengl
--enable-sdl2 --enable-pocketsphinx --enable-libmfx --enable-libdc1394
--enable-libdrm --enable-libiec61883 --enable-nvenc
--enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
libavutil 56. 51.100 / 56. 51.100
libavcodec 58. 91.100 / 58. 91.100
libavformat 58. 45.100 / 58. 45.100
libavdevice 58. 10.100 / 58. 10.100
libavfilter 7. 85.100 / 7. 85.100
libavresample 4. 0. 0 / 4. 0. 0
libswscale 5. 7.100 / 5. 7.100
libswresample 3. 7.100 / 3. 7.100
libpostproc 55. 7.100 / 55. 7.100
[mpeg2video @ 0x55bd8aece580] Invalid frame dimensions 0x0.
Last message repeated 18 times
Input #0, mpegts, from 'http://10.39.40.173:5004/auto/v2.1':
Duration: N/A, start: 47689.440967, bitrate: N/A
Program 1
Stream #0:0[0x31]: Video: mpeg2video (Main) ([2][0][0][0] /
0x0002), yuv420p(tv, bt709, top first), 1920x1080 [SAR 1:1 DAR 16:9],
Closed Captions, 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc
Side data:
cpb: bitrate max/min/avg: 80000000/0/0 buffer size: 9781248
vbv_delay: N/A
Stream #0:1[0x34](eng): Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz,
stereo, fltp, 192 kb/s
Stream #0:2[0x35](eng): Audio: ac3 (AC-3 / 0x332D4341), 48000 Hz,
stereo, fltp, 96 kb/s
Stream mapping:
Stream #0:0 -> #0:0 (mpeg2video (native) -> hevc (hevc_qsv))
Stream #0:1 -> #0:1 (ac3 (native) -> aac (native))
Press [q] to stop, [?] for help
Output #0, hls, to '720p.m3u8':
Metadata:
encoder : Lavf58.45.100
Stream #0:0: Video: hevc (hevc_qsv), nv12, 1920x1080 [SAR 1:1 DAR
16:9], q=2-31, 1000 kb/s, 29.97 fps, 90k tbn, 29.97 tbc
Metadata:
encoder : Lavc58.91.100 hevc_qsv
Side data:
cpb: bitrate max/min/avg: 0/0/1000000 buffer size: 0 vbv_delay: N/A
Stream #0:1(eng): Audio: aac (LC), 48000 Hz, stereo, fltp, 64 kb/s
Metadata:
encoder : Lavc58.91.100 aac
[hls @ 0x55bd8aee7940] Opening '720p_000.ts' for writingrate=N/A
dup=29 drop=0 speed=2.59x
[hls @ 0x55bd8aee7940] Opening '720p.m3u8.tmp' for writing
[hls @ 0x55bd8aee7940] Opening '720p_001.ts' for writingrate=N/A
dup=29 drop=0 speed=2.35x
[hls @ 0x55bd8aee7940] Opening '720p.m3u8.tmp' for writing
[hls @ 0x55bd8aee7940] Opening '720p_002.ts' for writingrate=N/A
dup=29 drop=0 speed=2.24x
[hls @ 0x55bd8aee7940] Opening '720p.m3u8.tmp' for writing
[hls @ 0x55bd8aee7940] Opening '720p_003.ts' for writing
[hls @ 0x55bd8aee7940] Opening '720p.m3u8.tmp' for writing
frame= 194 fps= 62 q=-0.0 Lsize=N/A time=00:00:06.30 bitrate=N/A
dup=29 drop=0 speed=2.01x
video:8928kB audio:49kB subtitle:0kB other streams:0kB global
headers:0kB muxing overhead: unknown
[aac @ 0x55bd8aef87c0] Qavg: 149.014
Exiting normally, received signal 2.
I'm also seeing numerous mpeg2 and ac3 error in ffmpeg that other players
don't see. They end up showing in the output video as errors in audio and
video
[mpegts @ 0x564b2a15a340] Packet corrupt (stream = 0, dts =
1078791167).drop=0 speed=1.02x
[mpeg2video @ 0x564b2a187e40] ac-tex damaged at 10 10
[mpeg2video @ 0x564b2a187e40] ac-tex damaged at 11 6
[mpeg2video @ 0x564b2a187e40] ac-tex damaged at 11 9
[mpeg2video @ 0x564b2a187e40] Invalid mb type in P-frame at 16 31
[mpeg2video @ 0x564b2a187e40] ac-tex damaged at 11 3
[mpeg2video @ 0x564b2a187e40] ac-tex damaged at 48 4
[mpeg2video @ 0x564b2a187e40] Warning MVs not available
[mpeg2video @ 0x564b2a187e40] concealing 2413 DC, 2413 AC, 2413 MV errors
in P frame
[mpegts @ 0x564b2a15a340] PES packet size mismatch
[mpegts @ 0x564b2a15a340] Packet corrupt (stream = 1, dts = 1078742391).
[ac3 @ 0x564b2a1c8e40] exponent -1 is out-of-range
[ac3 @ 0x564b2a1c8e40] error decoding the audio block
Error while decoding stream #0:1: Error number -16976906 occurred
I cannot tell if this is due to support for 10th gen intel chips or
library issues on this Ubuntu 20.10 system. I updated from 20.04 to 20.10
hoping for updated support for qsv, these issues exist in 20.04 and 20.10.
My goal is to have a continuously running ffmpeg instance transcoding
MPEG2 to hevc/HLS but the output video is so flawed its difficult to watch
and the segfaults are a show stopper.
I have this system ready and waiting to run more tests if needed.
Thank you.
--
Ticket URL: <https://trac.ffmpeg.org/ticket/9054>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker
