I use ffmpeg 7.1 source build on windows and compilation configuration as follow:
configuration:
--toolchain=msvc
--arch=x86_64
--enable-x86asm
--enable-asm
--enable-shared
--enable-w32threads
--prefix=/D/build
When I use av_dump_format to print metadata of test.mp3, it display the incorrect information.
extern "C"
{
#include <libavformat/avformat.h>
}
int main()
{
av_log_set_level(AV_LOG_DEBUG);
auto url = "D:/music/test.mp3";
AVFormatContext* fmt;
auto ret = avformat_open_input(&fmt, url, nullptr, nullptr);
if (ret < 0)
{
av_log(nullptr, AV_LOG_ERROR, "Cannot open %s format : %s", url, av_err2str(ret));
exit(EXIT_FAILURE);
}
av_dump_format(fmt, 0, url, 0);
}
output
[AVFormatContext @ 000001768E65BC40] Opening 'D:/music/test.mp3' for reading
[file @ 000001768E65C180] Setting default whitelist 'file,crypto,data'
[mp3 @ 000001768E65BC40] Format mp3 probed with size=4096 and score=51
id3v2 ver:4 flags:00 len:35
[mp3 @ 000001768E65BC40] pad 576 576
[mp3 @ 000001768E65BC40] Skipping 0 bytes of junk at 462.
Input #0, mp3, from 'D:/music/test.mp3':
Metadata:
encoder : Lavf58.76.100
Duration: N/A, bitrate: N/A
Stream #0:0, 0, 1/14112000: Audio: mp3, 0 channels
Metadata:
encoder : Lavc58.13
You can see the Stream info is useless.
But I use ffprobe which is built with same configuration to print metadata of test.mp3.
It's display normal.
ffprobe version 7.0.1 Copyright (c) 2007-2024 the FFmpeg developers
built with Microsoft (R) C/C++ Optimizing Compiler Version 19.41.34123 for x64
configuration: --toolchain=msvc --arch=x86_64 --enable-x86asm --enable-asm --enable-shared --enable-w32threads --prefix=/D/build
WARNING: library configuration mismatch
avutil configuration: --toolchain=msvc --arch=x86_64 --enable-x86asm --enable-asm --enable-shared --enable-w32threads --disable-programs --disable-doc --disable-static --prefix=/D/build
avcodec configuration: --toolchain=msvc --arch=x86_64 --enable-x86asm --enable-asm --enable-shared --enable-w32threads --disable-programs --disable-doc --disable-static --prefix=/D/build
avformat configuration: --toolchain=msvc --arch=x86_64 --enable-x86asm --enable-asm --enable-shared --enable-w32threads --disable-programs --disable-doc --disable-static --prefix=/D/build
avdevice configuration: --toolchain=msvc --arch=x86_64 --enable-x86asm --enable-asm --enable-shared --enable-w32threads --disable-programs --disable-doc --disable-static --prefix=/D/build
avfilter configuration: --toolchain=msvc --arch=x86_64 --enable-x86asm --enable-asm --enable-shared --enable-w32threads --disable-programs --disable-doc --disable-static --prefix=/D/build
swscale configuration: --toolchain=msvc --arch=x86_64 --enable-x86asm --enable-asm --enable-shared --enable-w32threads --disable-programs --disable-doc --disable-static --prefix=/D/build
swresample configuration: --toolchain=msvc --arch=x86_64 --enable-x86asm --enable-asm --enable-shared --enable-w32threads --disable-programs --disable-doc --disable-static --prefix=/D/build
libavutil 59. 8.100 / 59. 39.100
libavcodec 61. 3.100 / 61. 19.100
libavformat 61. 1.100 / 61. 7.100
libavdevice 61. 1.100 / 61. 3.100
libavfilter 10. 1.100 / 10. 4.100
libswscale 8. 1.100 / 8. 3.100
libswresample 5. 1.100 / 5. 3.100
Input #0, mp3, from 'D:\music\test.mp3':
Metadata:
encoder : Lavf58.76.100
Duration: 00:05:00.12, start: 0.025057, bitrate: 128 kb/s
Stream #0:0: Audio: mp3 (mp3float), 44100 Hz, stereo, fltp, 128 kb/s
Metadata:
encoder : Lavc58.13
Why is av_dump_format not correctly showing stream information? How can I fix it?
You need to run
ret = avformat_find_stream_info(fmt, NULL);
before dumping.
Hopefully, you have decoders enabled.