[FFmpeg-trac] #4348(undetermined:new): Slight audio latency when grabbing system audio from pulseaudio
FFmpeg
trac at avcodec.org
Tue Mar 3 11:51:05 CET 2015
#4348: Slight audio latency when grabbing system audio from pulseaudio
-------------------------------------+-------------------------------------
Reporter: skriticos | Type: defect
Status: new | Priority: normal
Component: | Version: git-
undetermined | master
Keywords: pulseaudio | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
-------------------------------------+-------------------------------------
Summary of the bug:
I'm doing screen-recordings in which I mix system audio from pulse and
audio from an external microphone. The recording works, but the system
audio has a slight delay (< 1 sec), just enough to be annoying.
The recording output shows two different warning messages:
1: [pulse @ 0x2804980] pa_stream_get_latency() failed
2:
[alsa @ 0x282d860] Thread message queue blocking; consider raising the
thread_queue_size option (current value: 8)
[output stream 0:0 @ 0x2848f40] 100 buffers queued in output stream 0:0,
something may be wrong.
[x11grab @ 0x283f220] Thread message queue blocking; consider raising the
thread_queue_size option (current value: 8)
[pulse @ 0x2804980] Thread message queue blocking; consider raising the
thread_queue_size option (current value: 8)
How to reproduce:
I'm using the following command to record the video. The first part grabs
the microphone and system audio stream and mixes them together, then the
video and puts it all together into a matroska file with one merged audio
stream and one video stream of the desktop.
{{{
nice -10 ffmpeg \
-f pulse -i alsa_output.pci-0000_00_1b.0.analog-stereo.monitor \
-f alsa -i hw:1,0 \
-filter_complex amix -async 1 \
-f x11grab -r 30 -s hd1080 -i :0.0 \
-map 0:a -map 2:v \
-acodec libvorbis -ab 160k \
-vcodec libx264 -tune stillimage -crf 12 -preset ultrafast \
-threads 4 \
-y \
$1.mkv
}}}
ffmpeg version: efd3f407e50ec04eb9b90825bf8436f221e65de8
Compiled form git master today.
Configuration:
% ./configure --enable-gpl --enable-pthreads --enable-libpulse --enable-
libx264 --enable-libvorbis --enable-libmp3lame --enable-libopus --extra-
libs=-lasound
Full recording output:
{{{
% record-fs-dual-audio.sh test
ffmpeg version N-70373-gefd3f40 Copyright (c) 2000-2015 the FFmpeg
developers
built with gcc 4.9.1 (Ubuntu 4.9.1-16ubuntu6)
configuration: --enable-gpl --enable-pthreads --enable-libpulse
--enable-libx264 --enable-libvorbis --enable-libmp3lame --enable-libopus
--extra-libs=-lasound
libavutil 54. 19.100 / 54. 19.100
libavcodec 56. 26.100 / 56. 26.100
libavformat 56. 23.106 / 56. 23.106
libavdevice 56. 4.100 / 56. 4.100
libavfilter 5. 11.102 / 5. 11.102
libswscale 3. 1.101 / 3. 1.101
libswresample 1. 1.100 / 1. 1.100
libpostproc 53. 3.100 / 53. 3.100
[pulse @ 0x25b9980] pa_stream_get_latency() failed
Last message repeated 1 times
Guessed Channel Layout for Input Stream #0.0 : stereo
Input #0, pulse, from 'alsa_output.pci-0000_00_1b.0.analog-
stereo.monitor':
Duration: N/A, start: 1425379593.636540, bitrate: 1536 kb/s
Stream #0:0: Audio: pcm_s16le, 48000 Hz, 2 channels, s16, 1536 kb/s
Guessed Channel Layout for Input Stream #1.0 : stereo
Input #1, alsa, from 'hw:1,0':
Duration: N/A, start: 1425379594.028598, bitrate: 1536 kb/s
Stream #1:0: Audio: pcm_s16le, 48000 Hz, 2 channels, s16, 1536 kb/s
[x11grab @ 0x25f3e60] Stream #0: not enough frames to estimate rate;
consider increasing probesize
Input #2, x11grab, from ':0.0':
Duration: N/A, bitrate: N/A
Stream #2:0: Video: rawvideo (BGR[0] / 0x524742), bgr0, 1920x1080, 30
fps, 30 tbr, 1000k tbn, 30 tbc
-async is forwarded to lavfi similarly to -af
aresample=async=1:min_hard_comp=0.100000:first_pts=0.
Last message repeated 1 times
No pixel format specified, yuv444p for H.264 encoding chosen.
Use -pix_fmt yuv420p for compatibility with outdated media players.
[libx264 @ 0x260a900] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2
AVX
[libx264 @ 0x260a900] profile High 4:4:4 Predictive, level 4.0, 4:4:4
8-bit
[libx264 @ 0x260a900] 264 - core 142 r2431 a5831aa - H.264/MPEG-4 AVC
codec - Copyleft 2003-2014 - http://www.videolan.org/x264.html - options:
cabac=0 ref=1 deblock=0:-3:-3 analyse=0:0 me=dia subme=0 psy=1
psy_rd=2.00:0.70 mixed_ref=0 me_range=16 chroma_me=1 trellis=0 8x8dct=0
cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=6 threads=4
lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0
bluray_compat=0 constrained_intra=0 bframes=0 weightp=0 keyint=250
keyint_min=25 scenecut=0 intra_refresh=0 rc=crf mbtree=0 crf=12.0
qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=0
Output #0, matroska, to 'test.mkv':
Metadata:
encoder : Lavf56.23.106
Stream #0:0: Audio: vorbis (libvorbis) (oV[0][0] / 0x566F), 48000 Hz,
stereo, fltp, 160 kb/s (default)
Metadata:
encoder : Lavc56.26.100 libvorbis
Stream #0:1: Video: h264 (libx264) (H264 / 0x34363248), yuv444p,
1920x1080, q=-1--1, 30 fps, 1k tbn, 30 tbc
Metadata:
encoder : Lavc56.26.100 libx264
Stream mapping:
Stream #0:0 (pcm_s16le) -> amix:input0 (graph 0)
Stream #1:0 (pcm_s16le) -> amix:input1 (graph 0)
amix (graph 0) -> Stream #0:0 (libvorbis)
Stream #2:0 -> #0:1 (rawvideo (native) -> h264 (libx264))
Press [q] to stop, [?] for help
[alsa @ 0x25e2800] Thread message queue blocking; consider raising the
thread_queue_size option (current value: 8)
[output stream 0:0 @ 0x25fd6a0] 100 buffers queued in output stream 0:0,
something may be wrong.
[x11grab @ 0x25f3e60] Thread message queue blocking; consider raising the
thread_queue_size option (current value: 8)
[pulse @ 0x25b9980] Thread message queue blocking; consider raising the
thread_queue_size option (current value: 8)
frame= 158 fps= 30 q=-1.0 Lsize= 2906kB time=00:00:05.26
bitrate=4520.4kbits/s
video:2831kB audio:68kB subtitle:0kB other streams:0kB global headers:4kB
muxing overhead: 0.273924%
[libx264 @ 0x260a900] frame I:1 Avg QP: 9.00 size:531756
[libx264 @ 0x260a900] frame P:157 Avg QP: 3.13 size: 15072
[libx264 @ 0x260a900] mb I I16..4: 100.0% 0.0% 0.0%
[libx264 @ 0x260a900] mb P I16..4: 0.5% 0.0% 0.0% P16..4: 7.0% 0.0%
0.0% 0.0% 0.0% skip:92.5%
[libx264 @ 0x260a900] coded y,u,v intra: 22.3% 23.4% 23.3% inter: 1.9%
1.8% 1.8%
[libx264 @ 0x260a900] i16 v,h,dc,p: 79% 19% 2% 0%
[libx264 @ 0x260a900] kb/s:4402.05
Received signal 2: terminating.
}}}
--
Ticket URL: <https://trac.ffmpeg.org/ticket/4348>
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