ffmpeg aac random errors in right channel

[jb_alvarado]

ffmpeg aac random errors in right channel

I have here a video which the native aac codec produce errors in the right channel. Same video with libfdk_aac works fine.

Full command ist:

ffmpeg -i /trunk/mel.mp4 -ss 9 -t 50 -s 320x180 -c:v libx264 -c:a aac -b:a 128k mel_aac.mp4

Full output:

ffmpeg -i /trunk/mel.mp4 -ss 9 -t 50 -s 320x180 -c:v libx264 -c:a aac -b:a 128k mel_aac.mp4
ffmpeg version N-81019-g3257ed8-ge29d2d9+1 Copyright (c) 2000-2016 the FFmpeg developers
  built with gcc 5.4.0 (Rev1, Built by MSYS2 project)
  configuration:  --enable-avisynth --enable-libmp3lame --enable-libopus --enable-libvorbis --enable-libx264 --enable-libx265 --enable-libzimg --enable-opengl --enable-libfdk-aac --enable-gpl --enable-nonfree --disable-debug
  libavutil      55. 28.100 / 55. 28.100
  libavcodec     57. 50.100 / 57. 50.100
  libavformat    57. 41.100 / 57. 41.100
  libavdevice    57.  0.102 / 57.  0.102
  libavfilter     6. 47.100 /  6. 47.100
  libswscale      4.  1.100 /  4.  1.100
  libswresample   2.  1.100 /  2.  1.100
  libpostproc    54.  0.100 / 54.  0.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'D:/_System/msys2-64-Ma16/mel.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf56.40.101
  Duration: 00:02:00.00, start: 0.010000, bitrate: 2121 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1024x576 [SAR 1:1 DAR 16:9], 1914 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 206 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
[libx264 @ 000001a32d8c8740] using SAR=1/1
[libx264 @ 000001a32d8c8740] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
[libx264 @ 000001a32d8c8740] profile High, level 1.2
[libx264 @ 000001a32d8c8740] 264 - core 148 r2705 3f5ed56 - H.264/MPEG-4 AVC codec - Copyleft 2003-2016 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 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=6 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=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
[mp4 @ 000001a32d94e7e0] Using AVStream.codec to pass codec parameters to muxers is deprecated, use AVStream.codecpar instead.
    Last message repeated 1 times
Output #0, mp4, to 'mel_aac.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf57.41.100
    Stream #0:0(und): Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv420p, 320x180 [SAR 1:1 DAR 16:9], q=-1--1, 25 fps, 12800 tbn, 25 tbc (default)
    Metadata:
      handler_name    : VideoHandler
      encoder         : Lavc57.50.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
    Stream #0:1(und): Audio: aac (LC) ([64][0][0][0] / 0x0040), 48000 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
      encoder         : Lavc57.50.100 aac
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264))
  Stream #0:1 -> #0:1 (aac (native) -> aac (native))
Press [q] to stop, [?] for help
frame= 1250 fps=271 q=-1.0 Lsize=    1710kB time=00:00:50.00 bitrate= 280.1kbits/s speed=10.8x
video:861kB audio:811kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 2.287036%
[libx264 @ 000001a32d8c8740] frame I:6     Avg QP:20.45  size:  8138
[libx264 @ 000001a32d8c8740] frame P:371   Avg QP:24.12  size:  1534
[libx264 @ 000001a32d8c8740] frame B:873   Avg QP:29.97  size:   301
[libx264 @ 000001a32d8c8740] consecutive B-frames:  3.8%  7.7%  5.0% 83.5%
[libx264 @ 000001a32d8c8740] mb I  I16..4:  4.7% 35.6% 59.7%
[libx264 @ 000001a32d8c8740] mb P  I16..4:  0.4%  1.3%  2.0%  P16..4: 23.9% 17.0% 11.8%  0.0%  0.0%    skip:43.5%
[libx264 @ 000001a32d8c8740] mb B  I16..4:  0.0%  0.0%  0.1%  B16..8: 20.6%  7.0%  1.9%  direct: 1.4%  skip:68.9%  L0:32.9% L1:49.6% BI:17.4%
[libx264 @ 000001a32d8c8740] 8x8 transform intra:35.1% inter:47.7%
[libx264 @ 000001a32d8c8740] coded y,uvDC,uvAC intra: 67.8% 70.5% 43.8% inter: 8.9% 4.7% 0.5%
[libx264 @ 000001a32d8c8740] i16 v,h,dc,p: 62%  6% 11% 21%
[libx264 @ 000001a32d8c8740] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 45%  6% 19%  5%  4%  7%  3%  6%  4%
[libx264 @ 000001a32d8c8740] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 49%  9% 13%  4%  4%  7%  4%  6%  4%
[libx264 @ 000001a32d8c8740] i8c dc,h,v,p: 44% 11% 40%  5%
[libx264 @ 000001a32d8c8740] Weighted P-Frames: Y:0.8% UV:0.3%
[libx264 @ 000001a32d8c8740] ref P L0: 67.2% 15.5% 11.6%  5.7%  0.0%
[libx264 @ 000001a32d8c8740] ref B L0: 92.3%  5.8%  1.9%
[libx264 @ 000001a32d8c8740] ref B L1: 97.0%  3.0%
[libx264 @ 000001a32d8c8740] kb/s:140.90
[aac @ 000001a32d8dd6c0] Qavg: 515.893

If you have a chance to put the audio in a audio editor and zoom very close in, you see that there is a clipping error, or something else. But only in the right channel. And if I recompress the same file, the errors will be on the same place.

You found the errors on second:
3.64
29.93
35.178
35.989
42.602

Looks like that this is only happen by 128k, because the source file has already a aac native compression with 192k.

Files are in the attachment.

[jb_alvarado]

Source File

[jb_alvarado]

damaged file

[jb_alvarado]

well file

[Rostislav Pehlivanov]

I can't hear any clipping on my headphones.
Please do not use an audio editor to report any bugs to lossy audio codecs. If you can't hear it it's not a bug.

[jb_alvarado]

First I hear this error because I had use this file for a livestream, using ffmpeg rtmp to wowza. And there it was even worse. After that I analyze the video and find out that what I describe at the top post.

Is not exactly a clipping, is more like a scratching, but in the audio editor it looks like that there is for a short moment almost no volume.