[FFmpeg-trac] #1693(avcodec:new): AAC Scalable Sample Rate (SSR)

FFmpeg trac at avcodec.org
Wed Feb 14 21:59:14 EET 2018

#1693: AAC Scalable Sample Rate (SSR)
             Reporter:  cehoyos     |                    Owner:
                 Type:  defect      |                   Status:  new
             Priority:  normal      |                Component:  avcodec
              Version:  git-master  |               Resolution:
             Keywords:  aac         |               Blocked By:
             Blocking:              |  Reproduced by developer:  0
Analyzed by developer:  0           |

Comment (by cehoyos):

 Replying to [comment:9 dalecurtis]:
 > This became an issue in Chrome because we stopped silently dropping
 these packets and instead started emitting an error. Skipping the SSR
 packet (like we did in M63 and below) leads to an accumulation of ~1
 seconds of audio loss every 10 seconds.

 If I understand correctly, you are saying that the sample you uploaded
 that plays for approximately 19.5 seconds with current FFmpeg, is supposed
 to play longer.

 > Given the volume of complaints quite a few folks have been silently
 losing their audio over the years. The workaround for now is to re-encode
 with libfdk_aac which can parse the SSR packets:
 > ./ffmpeg -acodec libfdk_aac -i <file> -acodec libfdk_aac -vcodec copy
 <out file>

 I tested the following command line:
 $ ffmpeg -acodec libfdk_aac -i ssr_chrome.aac -acodec libfdk_aac out.aac
 The output file plays for approximately 17 seconds: What did I

Ticket URL: <https://trac.ffmpeg.org/ticket/1693#comment:11>
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