#4861: AC3 audio glitch : exponent out-of-range
-------------------------------------+-------------------------------------
Reporter: Guillaume | Type: defect
Status: new | Priority: normal
Component: avcodec | Version: git-
Keywords: AC3 audio | master
glitch | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
-------------------------------------+-------------------------------------
I'm trying to decode an AC3 file extracted from live French TV stream.
3 audio glitches can be heard in the sample file.
During conversion, error logs are returned.
$ ffmpeg -i audio_ac3_glitch.ac3 audio_test.wav
ffmpeg version 2.7 Copyright (c) 2000-2015 the FFmpeg developers
built with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)
configuration:
libavutil 54. 27.100 / 54. 27.100
libavcodec 56. 41.100 / 56. 41.100
libavformat 56. 36.100 / 56. 36.100
libavdevice 56. 4.100 / 56. 4.100
libavfilter 5. 16.101 / 5. 16.101
libswscale 3. 1.101 / 3. 1.101
libswresample 1. 2.100 / 1. 2.100
[eac3 @ 0xa387a00] Estimating duration from bitrate, this may be
inaccurate
Input #0, eac3, from 'audio_ac3_glitch.ac3':
Duration: 00:00:45.57, start: 0.000000, bitrate: 127 kb/s
Stream #0:0: Audio: eac3, 48000 Hz, stereo, fltp, 128 kb/s
Output #0, wav, to 'audio_test.wav':
Metadata:
ISFT : Lavf56.36.100
Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 48000 Hz,
stereo, s16, 1536 kb/s
Metadata:
encoder : Lavc56.41.100 pcm_s16le
Stream mapping:
Stream #0:0 -> #0:0 (eac3 (native) -> pcm_s16le (native))
Press [q] to stop, [?] for help
[eac3 @ 0xa388be0] exponent out-of-range
[eac3 @ 0xa388be0] error decoding the audio block
[eac3 @ 0xa388be0] exponent out-of-range
[eac3 @ 0xa388be0] error decoding the audio block
[eac3 @ 0xa388be0] exponent out-of-range
[eac3 @ 0xa388be0] error decoding the audio block
[eac3 @ 0xa388be0] incomplete frame
size= 8550kB time=00:00:45.60 bitrate=1536.0kbits/s
video:0kB audio:8550kB subtitle:0kB other streams:0kB global headers:0kB
muxing overhead: 0.000891%
Same errors occur when trying to stream this file using a GSTreamer
pipeline :
gst-launch-1.0 -v --gst-debug-level=3 filesrc
location=./audio_ac3_glitch.ac3 ! ac3parse ! avdec_eac3 ! audioconvert !
playsink
We can notice that the errors seem related to audio glitches heard.
I've tried to modify the code in file libavcodec/ac3dec.c in function
ac3_decode_frame() where trying to decode the audio blocks generates the
log "error decoding the audio block\n". Without success.
--
Ticket URL: <https://trac.ffmpeg.org/ticket/4861>
FFmpeg <https://ffmpeg.org>
FFmpeg issue tracker
_______________________________________________
FFmpeg-trac mailing list
FFmpeg-trac@avcodec.org
http://ffmpeg.org/mailman/listinfo/ffmpeg-trac
