[FFmpeg-trac] #1848(avcodec:new): AMR-NB Q bit ignored
FFmpeg
trac at avcodec.org
Fri Oct 26 14:16:26 CEST 2012
#1848: AMR-NB Q bit ignored
------------------------------------+-----------------------------------
Reporter: krisha | Owner:
Type: defect | Status: new
Priority: normal | Component: avcodec
Version: git-master | Resolution:
Keywords: amrnb | Blocked By:
Blocking: | Reproduced by developer: 0
Analyzed by developer: 0 |
------------------------------------+-----------------------------------
Comment (by krisha):
I can not give you a command line or console output for that. This I saw
inside the code. And since this variable is not READ anywhere I know that
it is not used. There is also no output logging for this variable.
Steps to reproduce in case someone wnats to solve it:
1. Create a AMRNB file with 12.2 kbps and some seconds of silence
2. Each frame starts with 0x3C and 32 bytes of data, starting directly
after header
3. Modify one 0x3C to 0x38 (Q bit cleared) and add change some random bits
inside the 32 bytes of data.
4. watch the waveform or listen to it
Actually it does not matter if the header is 0x3C or 0x38. The frame will
be played or displayed anyway with the corrupt data. If I understood the
RFC right, it should not be played back but just used to improve overall
quality.
If someone wants to fix it, I'm here to explain in detail or to provide
samples.
--
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/1848#comment:2>
FFmpeg <http://ffmpeg.org>
FFmpeg issue tracker
More information about the FFmpeg-trac
mailing list