[FFmpeg-user] Getting peak bit rate info for HLS .m3u8 master playlist

[Joel Lopez]

On Wed, Nov 16, 2016 at 2:54 PM, Moritz Barsnick <barsnick at gmx.net> wrote:
> On Wed, Nov 16, 2016 at 20:12:49 +0100, Carl Eugen Hoyos wrote:
>> 2016-11-16 19:50 GMT+01:00 Joel Lopez <badassmexican at gmail.com>:
>> > looking at?  Do/How I look at the frames?  Where do I look to get this
>> > non-trivial info?  I can script it out once I know where to look.
>>
>> Forgive me for being unclear:
>> It is so difficult that I don't know how to do it and I don't know where
>> to look (but I do know that if you were able to do it you wouldn't have
>> to ask).
>>
>> (This is not about finding the biggest frame in a stream afaik, this
>> would of course be trivial.)
>
> I found this information:
>
> http://ramugedia.com/hls--how-determine-peak-bitrate
> (which doesn't point to any source for this info).
>
> It does look scriptable. It would be more difficult to implement for
> ffmpeg, as the hls demuxer would need to keep a memory of each
> segment's properties, and do the math at the end, but perhaps not
> impossible.
>
> Moritz
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Thanks Moritz.  I found that today too but my eyes glazed over as I
looked at the calculation.  I think I'll bite the bullet and try to
figure it out.

I also found this today and it prints out what it says is a peak
bitrate.  I got it to work on my machine but I'm not sure if it's
giving me the same number as Media Stream Validator.

http://stackoverflow.com/questions/26220557/how-to-get-h264-bitrate

#!/bin/bash

# Mimic the output of
# mplayer -lavdopts vstats FILE -fps 30 -vo null
# Example usage:
# ./vstats.sh file.hevc 30

FFPROBE=$HOME/src/ffmpeg/ffprobe

fps=$2
# default 30 fps
: ${fps:=30}

frames=$3
# Numper of frames to process
: ${frames:=65536}

awk -v FPS="${fps}" -v FRAMES="${frames}" '
BEGIN{
    FS="="
}
/pkt_size/ {
  br=$2/1000.0*8*FPS
  if (br > max_br)
      max_br=br
  acc_br+=br
  acc_bytes+=br
  i+=1
  printf("frame= %6d, f_size= %7d, s_size= %8dkB, br= %8.1fkbits/s,
avg_br= %8.1fkbits/s\n",
      i, $2, int(acc_bytes/1024+0.5), br, acc_br/i)

  if (i >= FRAMES)
      exit
}
END {
    print "----"
    printf("Peak BR: %.1fkbits/s", max_br)
}
' <(${FFPROBE} -show_frames $1 2>/dev/null)

Example output:

frame=      1, f_size=   50805, s_size=       12kB, br=
12193.2kbits/s, avg_br=  12193.2kbits/s
frame=      2, f_size=    4749, s_size=       13kB, br=
1139.8kbits/s, avg_br=   6666.5kbits/s
frame=      3, f_size=    5781, s_size=       14kB, br=
1387.4kbits/s, avg_br=   4906.8kbits/s
frame=      4, f_size=    6135, s_size=       16kB, br=
1472.4kbits/s, avg_br=   4048.2kbits/s
frame=      5, f_size=    6239, s_size=       17kB, br=
1497.4kbits/s, avg_br=   3538.0kbits/s
frame=      6, f_size=    6487, s_size=       19kB, br=
1556.9kbits/s, avg_br=   3207.8kbits/s
frame=      7, f_size=    6550, s_size=       20kB, br=
1572.0kbits/s, avg_br=   2974.1kbits/s
frame=      8, f_size=    6567, s_size=       22kB, br=
1576.1kbits/s, avg_br=   2799.4kbits/s
frame=      9, f_size=    6390, s_size=       23kB, br=
1533.6kbits/s, avg_br=   2658.7kbits/s
frame=     10, f_size=    6540, s_size=       25kB, br=
1569.6kbits/s, avg_br=   2549.8kbits/s
frame=     11, f_size=    6929, s_size=       27kB, br=
1663.0kbits/s, avg_br=   2469.2kbits/s
frame=     12, f_size=    8037, s_size=       28kB, br=
1928.9kbits/s, avg_br=   2424.2kbits/s
frame=     13, f_size=    7965, s_size=       30kB, br=
1911.6kbits/s, avg_br=   2384.8kbits/s
frame=     14, f_size=    7833, s_size=       32kB, br=
1879.9kbits/s, avg_br=   2348.7kbits/s
frame=     15, f_size=    8281, s_size=       34kB, br=
1987.4kbits/s, avg_br=   2324.6kbits/s
frame=     16, f_size=    8235, s_size=       36kB, br=
1976.4kbits/s, avg_br=   2302.8kbits/s
frame=     17, f_size=    7969, s_size=       38kB, br=
1912.6kbits/s, avg_br=   2279.9kbits/s
frame=     18, f_size=    7953, s_size=       40kB, br=
1908.7kbits/s, avg_br=   2259.3kbits/s
frame=     19, f_size=    8867, s_size=       42kB, br=
2128.1kbits/s, avg_br=   2252.4kbits/s
frame=     20, f_size=    9686, s_size=       44kB, br=
2324.6kbits/s, avg_br=   2256.0kbits/s
----
Peak BR: 12193.2kbits/s