I was studying the ffpresets and avpresets but I stumbled upon something interesting.
According to the ffmpeg docs:
First ffmpeg searches for a file named codec_name-arg.avpreset in the above-mentioned directories, where codec_name is the name of the codec to which the preset file options will be applied. For example, if you select the video codec with -vcodec libvpx and use -pre 1080p, then it will search for the file libvpx-1080p.avpreset.
If no such file is found, then ffmpeg will search for a file named arg.avpreset in the same directories.
I have a preset stored in the correct directory:
$ ls ~/.avconv/
libvpx-1080p.avpreset
Therefore, the following command should work:
$ ffmpeg -i input.mp4 -vcodec libvpx -pre 1080p output.mp4
But instead it results in the follwing error:
Preset 1080p specified for stream 0:1, but could not be opened.
However, the following command works:
ffmpeg -i input.mp4 -vcodec libvpx -pre libvpx-1080p output.mp4
Is this a bug or am I misunderstanding the docs?
EDIT: I originally tried with the latest ffmpeg version available from the repositories (4.3.1). However, I then decided to confirm this is still the case with the latest version built from source, which yields:
~/Downloads/FFmpeg$ ./ffmpeg --version
ffmpeg version N-102649-g3ac7d99428 Copyright (c) 2000-2021 the FFmpeg developers
built with gcc 10 (Ubuntu 10.2.0-13ubuntu1)
configuration: --disable-x86asm --enable-libvpx
libavutil 57. 0.100 / 57. 0.100
libavcodec 59. 1.100 / 59. 1.100
libavformat 59. 2.101 / 59. 2.101
libavdevice 59. 0.100 / 59. 0.100
libavfilter 8. 0.101 / 8. 0.101
libswscale 6. 0.100 / 6. 0.100
libswresample 4. 0.100 / 4. 0.100
EDIT 2: Adding the whole log of the failing command as requested
$ ./ffmpeg -i ../input.mp4 -vcodec libvpx -pre 1080p ../output.mp4
ffmpeg version N-102649-g3ac7d99428 Copyright (c) 2000-2021 the FFmpeg developers
built with gcc 10 (Ubuntu 10.2.0-13ubuntu1)
configuration: --disable-x86asm --enable-libvpx
libavutil 57. 0.100 / 57. 0.100
libavcodec 59. 1.100 / 59. 1.100
libavformat 59. 2.101 / 59. 2.101
libavdevice 59. 0.100 / 59. 0.100
libavfilter 8. 0.101 / 8. 0.101
libswscale 6. 0.100 / 6. 0.100
libswresample 4. 0.100 / 4. 0.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '../input.mp4':
Metadata:
major_brand : mp42
minor_version : 0
compatible_brands: mp42mp41isomavc1
creation_time : 2015-08-07T09:13:36.000000Z
Duration: 00:00:30.53, start: 0.000000, bitrate: 4675 kb/s
Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 1920x1080 [SAR 1:1 DAR 16:9], 4486 kb/s, 30 fps, 30 tbr, 30 tbn (default)
Metadata:
creation_time : 2015-08-07T09:13:36.000000Z
handler_name : L-SMASH Video Handler
vendor_id : [0][0][0][0]
encoder : AVC Coding
Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 256 kb/s (default)
Metadata:
creation_time : 2015-08-07T09:13:36.000000Z
handler_name : L-SMASH Audio Handler
vendor_id : [0][0][0][0]
Preset 1080p specified for stream 0:1, but could not be opened.
The -pre option accepts stream specifiers and in the absence of any, will be applied to all streams. Since the default audio encoder for MP4 is aac, ffmpeg will look for aac-1080p.avpreset and then 1080p.avpreset Since neither of those exist, ffmpeg errors out.
Change -pre to either -vpre or -pre:v.