[FFmpeg-trac] #4544(avcodec:open): Problem transcoding 5.1 AAC LATM audio streams

FFmpeg trac at avcodec.org
Wed Feb 1 23:00:27 EET 2017

#4544: Problem transcoding 5.1 AAC LATM audio streams
             Reporter:  chq.contact   |                    Owner:
                 Type:  defect        |                   Status:  open
             Priority:  normal        |                Component:  avcodec
              Version:  git-master    |               Resolution:
             Keywords:  aac latm sbr  |               Blocked By:
             Blocking:                |  Reproduced by developer:  1
Analyzed by developer:  0             |

Comment (by tmm1):

 DVB-T streams in Brazil and Singapore use AAC SSR (Scalable Sample Rate),
 and cannot be decoded by ffmpeg. On ffmpeg master, I see the following

     [aac_latm @ 0x7fe396001c00] SSR is not implemented. Update your FFmpeg
 version to the newest one from Git. If the problem still occurs, it means
 that your file has a feature which has not been implemented.

 According to https://lists.libav.org/pipermail/ffmpeg-
 devel/2008-July/049282.html, there was an implementation of SSR that never
 made it to master:

     The code for LTP and SSR is still in the Summer of Code repository for
 anyone who is interested in working on either of those features in the

 And according to https://en.wikipedia.org/wiki/MPEG-4_Part_3#AAC-SSR:

     MPEG-4 AAC-SSR is very similar to ATRAC and ATRAC-3.

 So the existing atrac and atrac3 decoders might be useful as well.

Ticket URL: <https://trac.ffmpeg.org/ticket/4544#comment:7>
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