[FFmpeg-trac] #4513(avdevice:new): Avfoundation Audio stutters / sounds broken with screen capture

FFmpeg trac at avcodec.org
Sun Apr 26 07:42:23 CEST 2015


#4513: Avfoundation Audio stutters / sounds broken with screen capture
-------------------------------------+-------------------------------------
             Reporter:  kevincast    |                     Type:  defect
               Status:  new          |                 Priority:  important
            Component:  avdevice     |                  Version:  git-
             Keywords:               |  master
  avfoundation audio                 |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug:
 I am trying to do a basic screen capture in OS X [10.10.3] with audio from
 mic using avfoundation.
 The recorded audio is stuttering, breaks, or there is short bursts.

 How to reproduce:
 {{{

 ffmpeg -f avfoundation -i "1:0" -r 25  -c:v libx264 -preset fast -crf 22
 -c:a libfdk_aac  -b:a 128k -ar 44100 -s 640x480 screen.mp4

 ffmpeg version: git-master and also version N-71716-g7b94a2f
 built on ... OS X 10.10.3
 }}}

 I tried different codec, bitrate, and audio is broken in all.
 While the same exact command with -i "0:0" for FaceTime camera has great
 audio quality.

 Here is link to the recorded file in which audio is broken:
 play on web: https://www.dropbox.com/s/p7ej68mrhi2te8r/screen.mp4?dl=0
 downloadable link:
 https://www.dropbox.com/s/p7ej68mrhi2te8r/screen.mp4?dl=1



 {{{
  ffmpeg -f avfoundation -i "1:0" -r 25  -c:v libx264 -preset fast -crf 22
 -c:a libfdk_aac  -b:a 128k -ar 44100 -s 640x480 screen.mp4
 ffmpeg version 2.6.1 Copyright (c) 2000-2015 the FFmpeg developers
   built with Apple LLVM version 6.1.0 (clang-602.0.49) (based on LLVM
 3.6.0svn)
   configuration: --prefix=/usr/local/Cellar/ffmpeg/2.6.1 --enable-shared
 --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables
 --enable-avresample --cc=clang --host-cflags= --host-ldflags=
 --enable-libx264 --enable-libmp3lame --enable-libvo-aacenc --enable-
 libxvid
 --enable-libfreetype --enable-libvorbis --enable-libvpx --enable-libfaac
 --enable-libass --enable-ffplay --enable-libfdk-aac --enable-openssl
 --enable-libopus --enable-libquvi --enable-libx265 --enable-nonfree
 --enable-vda
   libavutil      54. 20.100 / 54. 20.100
   libavcodec     56. 26.100 / 56. 26.100
   libavformat    56. 25.101 / 56. 25.101
   libavdevice    56.  4.100 / 56.  4.100
   libavfilter     5. 11.102 /  5. 11.102
   libavresample   2.  1.  0 /  2.  1.  0
   libswscale      3.  1.101 /  3.  1.101
   libswresample   1.  1.100 /  1.  1.100
   libpostproc    53.  3.100 / 53.  3.100
 [avfoundation @ 0x7f9b89001400] Selected pixel format (yuv420p) is not
 supported by the input device.
 [avfoundation @ 0x7f9b89001400] Supported pixel formats:
 [avfoundation @ 0x7f9b89001400]   uyvy422
 [avfoundation @ 0x7f9b89001400]   yuyv422
 [avfoundation @ 0x7f9b89001400]   nv12
 [avfoundation @ 0x7f9b89001400]   0rgb
 [avfoundation @ 0x7f9b89001400]   bgr0
 [avfoundation @ 0x7f9b89001400] Overriding selected pixel format to use
 uyvy422 instead.
 [avfoundation @ 0x7f9b89001400] Stream #0: not enough frames to estimate
 rate; consider increasing probesize
 Input #0, avfoundation, from '1:0':
   Duration: N/A, start: 0.368389, bitrate: N/A
     Stream #0:0: Video: rawvideo (UYVY / 0x59565955), uyvy422, 1440x900,
 1000k tbr, 1000k tbn, 1000k tbc
     Stream #0:1: Audio: pcm_f32le, 44100 Hz, stereo, flt, 2822 kb/s
 No pixel format specified, yuv422p for H.264 encoding chosen.
 Use -pix_fmt yuv420p for compatibility with outdated media players.
 [libx264 @ 0x7f9b89103200] using cpu capabilities: MMX2 SSE2Fast SSSE3
 SSE4.1 Cache64
 [libx264 @ 0x7f9b89103200] profile High 4:2:2, level 3.0, 4:2:2 8-bit
 [libx264 @ 0x7f9b89103200] 264 - core 144 r2533 c8a773e - H.264/MPEG-4 AVC
 codec - Copyleft 2003-2015 - http://www.videolan.org/x264.html - options:
 cabac=1 ref=2 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=6 psy=1
 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1
 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=3
 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0
 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1
 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=1 keyint=250 keyint_min=25
 scenecut=40 intra_refresh=0 rc_lookahead=30 rc=crf mbtree=1 crf=22.0
 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
 Output #0, mp4, to 'screen.mp4':
   Metadata:
     encoder         : Lavf56.25.101
     Stream #0:0: Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv422p,
 640x480, q=-1--1, 25 fps, 12800 tbn, 25 tbc
     Metadata:
       encoder         : Lavc56.26.100 libx264
     Stream #0:1: Audio: aac (libfdk_aac) ([64][0][0][0] / 0x0040), 44100
 Hz, stereo, s16, 128 kb/s
     Metadata:
       encoder         : Lavc56.26.100 libfdk_aac
 Stream mapping:
   Stream #0:0 -> #0:0 (rawvideo (native) -> h264 (libx264))
   Stream #0:1 -> #0:1 (pcm_f32le (native) -> aac (libfdk_aac))
 Press [q] to stop, [?] for help
 frame=  255 fps= 25 q=-1.0 Lsize=     286kB time=00:00:10.19 bitrate=
 229.8kbits/s dup=102 drop=0
 video:137kB audio:136kB subtitle:0kB other streams:0kB global headers:0kB
 muxing overhead: 4.737433%
 [libx264 @ 0x7f9b89103200] frame I:2     Avg QP:20.52  size: 46726
 [libx264 @ 0x7f9b89103200] frame P:65    Avg QP:23.32  size:   640
 [libx264 @ 0x7f9b89103200] frame B:188   Avg QP:31.27  size:    22
 [libx264 @ 0x7f9b89103200] consecutive B-frames:  1.6%  0.0%  1.2% 97.3%
 [libx264 @ 0x7f9b89103200] mb I  I16..4: 15.7% 48.2% 36.1%
 [libx264 @ 0x7f9b89103200] mb P  I16..4:  0.0%  0.0%  0.4%  P16..4:  0.8%
  0.1%  0.0%  0.0%  0.0%    skip:98.7%
 [libx264 @ 0x7f9b89103200] mb B  I16..4:  0.0%  0.0%  0.0%  B16..8:  0.2%
  0.0%  0.0%  direct: 0.0%  skip:99.8%  L0:38.8% L1:61.2% BI: 0.0%
 [libx264 @ 0x7f9b89103200] 8x8 transform intra:43.0% inter:2.5%
 [libx264 @ 0x7f9b89103200] coded y,uvDC,uvAC intra: 37.2% 37.7% 33.9%
 inter: 0.0% 0.1% 0.0%
 [libx264 @ 0x7f9b89103200] i16 v,h,dc,p: 60% 40%  0%  0%
 [libx264 @ 0x7f9b89103200] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 87%  8%  3%  0%
  0%  0%  0%  0%  1%
 [libx264 @ 0x7f9b89103200] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 23% 39% 12%  3%
  3%  3%  6%  3%  8%
 [libx264 @ 0x7f9b89103200] i8c dc,h,v,p: 74% 11% 14%  1%
 [libx264 @ 0x7f9b89103200] Weighted P-Frames: Y:0.0% UV:0.0%
 [libx264 @ 0x7f9b89103200] ref P L0: 73.8% 26.2%
 [libx264 @ 0x7f9b89103200] ref B L0: 95.1%  4.9%
 [libx264 @ 0x7f9b89103200] ref B L1: 95.1%  4.9%
 [libx264 @ 0x7f9b89103200] kb/s:109.18
 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/4513>
FFmpeg <https://ffmpeg.org>
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