lavc/aac_ac3_parser: improve the raw AAC file bit rate calculation
authorJun Zhao <barryjzhao@tencent.com>
Sun, 17 May 2020 04:10:05 +0000 (12:10 +0800)
committerJun Zhao <barryjzhao@tencent.com>
Fri, 26 Jun 2020 01:53:36 +0000 (09:53 +0800)
commit60d79b1df9d4c6030010ccb0c134ede9e33158c2
treeeca70df320e7b35240d68f1eed3a8f148a730203
parenta8fb7612a97530bdd0b2549dacf91dcf71a3187a
lavc/aac_ac3_parser: improve the raw AAC file bit rate calculation

Now we just use one ADTS raw frame to calculate the bit rate, it's
lead to a larger error when get the duration from bit rate, the
improvement cumulate Nth ADTS frames to get the average bit rate.

e,g used the command get the duration like:
ffprobe -show_entries format=duration -i fate-suite/aac/foo.aac

before this improvement dump the duration=2.173935
after this improvement  dump the duration=1.979267

in fact, the real duration can be get by command like:
ffmpeg -i fate-suite/aac/foo.aac -f null /dev/null with time=00:00:01.97

Also update the fate-adtstoasc_ticket3715.

Signed-off-by: Jun Zhao <barryjzhao@tencent.com>
libavcodec/aac_ac3_parser.c
libavcodec/aac_ac3_parser.h
tests/ref/fate/adtstoasc_ticket3715