#6205 closed defect (invalid)
Distortions in audio output when selecting input audio track 5 or higher
Reported by: | ackjewt | Owned by: | |
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Priority: | normal | Component: | avdevice |
Version: | git-master | Keywords: | decklink |
Cc: | Blocked By: | ||
Blocking: | Reproduced by developer: | no | |
Analyzed by developer: | no |
Description
Summary of the bug:
While using input track 5 or higher, i hear distortions in the output. I've attached two files, one using audio tracks 3-4 (sdi_576i_audio_ch_3-4.avi) and one using audio tracks 5-6 (sdi_576i_audio_ch_5-6.avi)
Input:
720x576i25, 8 audio tracks
Using:
CentOS 7
FFmpeg-git
Latest Decklink SDK (10.8.5)
How to reproduce:
ffmpeg -report -v 9 -loglevel 99 -re -channels 8 -f decklink -i "DeckLink SDI@3" -pixel_format uyvy422 -af "pan=stereo|c0=c4|c1=c5" -vn -acodec pcm_s16le sdi_576i_audio_ch_5-6.avi ffmpeg version N-83691-g7f62368 Copyright (c) 2000-2017 the FFmpeg developers built with gcc 4.8.5 (GCC) 20150623 (Red Hat 4.8.5-11) configuration: --prefix=/root/ffmpeg-static/target --pkg-config-flags=--static --extra-cflags=-I/root/ffmpeg-static/target/include --extra-ldflags=-L/root/ffmpeg-static/target/lib --bindir=/root/ffmpeg-static/bin --enable-decklink --extra-cflags=-I/usr/include/decklink-10.8.5 --extra-ldflags=-ldl --extra-libs=-ldl --enable-ffplay --enable-ffserver --enable-gpl --enable-libass --enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libopus --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-nonfree libavutil 55. 47.100 / 55. 47.100 libavcodec 57. 81.100 / 57. 81.100 libavformat 57. 66.102 / 57. 66.102 libavdevice 57. 3.100 / 57. 3.100 libavfilter 6. 74.100 / 6. 74.100 libswscale 4. 3.101 / 4. 3.101 libswresample 2. 4.100 / 2. 4.100 libpostproc 54. 2.100 / 54. 2.100
Attachments (1)
Change History (7)
comment:1 by , 7 years ago
comment:2 by , 7 years ago
Component: | undetermined → ffmpeg |
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Keywords: | decklink added; Decklink SDI Audio removed |
Did you upload the logs to an external location to make it less likely that a developer looks at the issue?
Please provide an output file for the following command:
$ ffmpeg -channels 8 -f decklink -i "DeckLink SDI@3" -acodec copy out.wav
by , 7 years ago
comment:3 by , 7 years ago
No, i thought that putting everything in the same place made more sense. Sorry for that.
I've attached the wav to the ticket. Let me know if you need a longer sample file.
comment:4 by , 7 years ago
Component: | ffmpeg → avdevice |
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I wanted to suggest -af "channelmap=4|5:stereo"
to fix your issue but the distortions are already in the decklink stream, not produced by the filter chain.
Do you have another possibility to record eight-channel audio from this device?
comment:5 by , 7 years ago
Resolution: | → fixed |
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Status: | new → closed |
Thank you for the suggestion. I was looking for something like that instead of the pan filter.
I've found the issue now. It was related to how the Decklink card is handling of "audio sample distribution" when using SD (576i in this case). The issue is not there when using HD. The issue is also solved on newer Decklink cards.
Apparently, the file size limit is 2.5MB, so i've uploaded the sample files and logs here:
https://www.dropbox.com/s/6ltughwd57g8za5/sdi_576i_audio_ch_5-6.avi?dl=1
https://www.dropbox.com/s/m05u5qhkk7lmvvq/sdi_576i_audio_ch_3-4.avi?dl=1
https://www.dropbox.com/s/szxgwztljp19dgy/ffmpeg-20170228-163730.log?dl=1
https://www.dropbox.com/s/kizvshm59k7nlxw/ffmpeg-20170228-163601.log?dl=1