The output I provided just happened to be one of the very few that used
AAC, and what I was using to compare bitrates. Most of my videos use
pcm_s16le, which I am understanding is not supported in MP4, and thus the
reason I am converting everything to AAC by default.
Example #2, input with pcm_s16le, input bitrate of 705 kb/s. Output bitrate
defaults to 69 kb/s. I would have expected the output bitrate to match that
of the input. Does AAC support that high of a bitrate?
ffmpeg version N-83749-g035e932 Copyright (c) 2000-2017 the FFmpeg
developers
built with gcc 6.3.0 (GCC)
configuration: --disable-static --enable-shared --enable-gpl
--enable-version3 --enable-cuda --enable-cuvid --enable-d3d11va
--enable-dxva2 --enable-libmfx --enable-nvenc --enable-avisynth
--enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls
--enable-iconv --enable-libass --enable-libbluray --enable-libbs2b
--enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm
--enable-libilbc --enable-libmodplug --enable-libmp3lame
--enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264
--enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libsnappy
--enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame
--enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis
--enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264
--enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg
--enable-lzma --enable-zlib
libavutil 55. 47.101 / 55. 47.101
libavcodec 57. 82.100 / 57. 82.100
libavformat 57. 66.103 / 57. 66.103
libavdevice 57. 3.100 / 57. 3.100
libavfilter 6. 74.100 / 6. 74.100
libswscale 4. 3.101 / 4. 3.101
libswresample 2. 4.100 / 2. 4.100
libpostproc 54. 2.100 / 54. 2.100
Guessed Channel Layout for Input Stream #0.1 : mono
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '100APPLE\IMG_0010.MOV':
Metadata:
major_brand : qt
minor_version : 0
compatible_brands: qt
creation_time : 2016-07-19T18:42:38.000000Z
com.apple.quicktime.content.identifier:
3118A852-CBA8-488D-9868-F883D5A19A73
com.apple.quicktime.location.ISO6709: +31.7345-106.3326+1141.214/
com.apple.quicktime.make: Apple
com.apple.quicktime.model: iPhone 6s Plus
com.apple.quicktime.software: 9.3.1
com.apple.quicktime.creationdate: 2016-07-19T12:42:38-0600
Duration: 00:00:02.67, start: 0.000000, bitrate: 8695 kb/s
Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuvj420p(pc,
smpte170m/bt709/bt709), 1440x1080, 7965 kb/s, 12.38 fps, 15 tbr, 600 tbn,
1200 tbc (default)
Metadata:
rotate : 90
creation_time : 2016-07-19T18:42:38.000000Z
handler_name : Core Media Data Handler
encoder : H.264
Side data:
displaymatrix: rotation of -90.00 degrees
Stream #0:1(und): Audio: pcm_s16le (lpcm / 0x6D63706C), 44100 Hz, mono,
s16, 705 kb/s (default)
Metadata:
creation_time : 2016-07-19T18:42:38.000000Z
handler_name : Core Media Data Handler
Stream #0:2(und): Data: none (mebx / 0x7862656D), 43 kb/s (default)
Metadata:
creation_time : 2016-07-19T18:42:38.000000Z
handler_name : Core Media Data Handler
Stream mapping:
Stream #0:0 -> #0:0 (copy)
Stream #0:1 -> #0:1 (pcm_s16le (native) -> aac (native))
Press [q] to stop, [?] for help
Output #0, mp4, to 'C:..\iPhone\DCIM\IMG_0010.MP4':
Metadata:
major_brand : qt
minor_version : 0
compatible_brands: qt
com.apple.quicktime.creationdate: 2016-07-19T12:42:38-0600
com.apple.quicktime.content.identifier:
3118A852-CBA8-488D-9868-F883D5A19A73
com.apple.quicktime.location.ISO6709: +31.7345-106.3326+1141.214/
com.apple.quicktime.make: Apple
com.apple.quicktime.model: iPhone 6s Plus
com.apple.quicktime.software: 9.3.1
encoder : Lavf57.66.103
Stream #0:0(und): Video: h264 (High) ([33][0][0][0] / 0x0021),
yuvj420p(pc, smpte170m/bt709/bt709), 1440x1080, q=2-31, 7965 kb/s, 12.38
fps, 15 tbr, 19200 tbn, 600 tbc (default)
Metadata:
rotate : 90
creation_time : 2016-07-19T18:42:38.000000Z
handler_name : Core Media Data Handler
encoder : H.264
Side data:
displaymatrix: rotation of -90.00 degrees
Stream #0:1(und): Audio: aac (LC) ([64][0][0][0] / 0x0040), 44100 Hz,
mono, fltp, 69 kb/s (default)
Metadata:
creation_time : 2016-07-19T18:42:38.000000Z
handler_name : Core Media Data Handler
encoder : Lavc57.82.100 aac
frame= 27 fps=0.0 q=-1.0 Lsize= 2334kB time=00:00:02.67
bitrate=7160.8kbits/s speed=18.8x
video:2309kB audio:23kB subtitle:0kB other streams:0kB global headers:0kB
muxing overhead: 0.095816%
[aac @ 000000000048dfc0] Qavg: 110.545
On Wed, Mar 8, 2017 at 11:21 AM, Cley Faye <cleyf...@gmail.com> wrote:
> 2017-03-08 17:56 GMT+01:00 Richard Duran <ricd...@gmail.com>:
>
> > From what I can tell of the following output, the input audio bitrate is
> 85
> > kb/s, and the output is 69 kb/s.
> >
> > I would like to know if it's possible to retain the source audio
> bitrate. I
> > am doing this via a batch file that loops through iPhone videos that have
> > varying bitrates.
> >
> >
> >
> > E:\> ffmpeg.exe -i 100APPLE\IMG_0075.MOV -vcodec copy -acodec aac
> > C:..\iPhone\DCIM\IMG_0075.MP4
> >
>
> Since your input already have aac audio, and you're already copying the
> video stream as-is, why not just "-codec copy" and be done with it?
>
> If you specify "-acodec aac" it will do a transcode, taking time, and use
> default values, which is obviously not what you want.
> Also, if you do want to transcode from aac to aac, there's no much point in
> trying to keep the same bitrate; it'll be lossy anyway.
> _______________________________________________
> ffmpeg-user mailing list
> ffmpeg-user@ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-user
>
> To unsubscribe, visit link above, or email
> ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
>
_______________________________________________
ffmpeg-user mailing list
ffmpeg-user@ffmpeg.org
http://ffmpeg.org/mailman/listinfo/ffmpeg-user
To unsubscribe, visit link above, or email
ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".
