How to convert mp4 file to mp3 file?

[michalkubizna]

I am executing this line of code:

executeAsyncFFmpeg("-i $audioSampleFile.mp4 $audioOutputFile.mp3").

Whenever I do that it prints this error message:

• Output #0, mp3, to '/data/user/0/com.arthenica.flutter.ffmpeg.FlutterFFmpegExample/app_flutter/audio.mp3':
• Output file #0 does not contain any stream
• Conversion failed! What am I doing wrong? There are no examples of video to audio conversions.

[tanersener]

That single line doesn't tell anything. Why don't you share full console output?

[michalkubizna]

Sure. Performing hot reload... Syncing files to device sdk gphone arm64... Reloaded 1 of 1466 libraries in 360ms. I/flutter (10630): File: '/data/user/0/com.terrant/app_flutter/audio.mp3' D/flutter-ffmpeg(10630): Running FFmpeg with arguments: [-i, /data/user/0/com.terrant/app_flutter/traffic.mp4, /data/user/0/com.terrant/app_flutter/audio.mp3]. I/mobile-ffmpeg(10630): ffmpeg version v4.4-dev-416 I/mobile-ffmpeg(10630): Copyright (c) 2000-2020 the FFmpeg developers I/mobile-ffmpeg(10630): I/mobile-ffmpeg(10630): built with Android (6454773 based on r365631c2) clang version 9.0.8 (https://android.googlesource.com/toolchain/llvm-project 98c855489587874b2a325e7a516b99d838599c6f) (based on LLVM 9.0.8svn) I/mobile-ffmpeg(10630): configuration: --cross-prefix=aarch64-linux-android- --sysroot=/files/android-sdk/ndk/21.3.6528147/toolchains/llvm/prebuilt/linux-x86_64/sysroot --prefix=/home/taner/Projects/mobile-ffmpeg/prebuilt/android-arm64/ffmpeg --pkg-config=/usr/bin/pkg-config --enable-version3 --arch=aarch64 --cpu=armv8-a --cc=aarch64-linux-android24-clang --cxx=aarch64-linux-android24-clang++ --extra-libs='-L/home/taner/Projects/mobile-ffmpeg/prebuilt/android-arm64/cpu-features/lib -lndk_compat' --target-os=android --enable-neon --enable-asm --enable-inline-asm --enable-cross-compile --enable-pic --enable-jni --enable-optimizations --enable-swscale --enable-shared --enable-v4l2-m2m --disable-outdev=fbdev --disable-indev=fbdev --enable-small --disable-openssl --disable-xmm-clobber-test --disable-debug --enable-lto --disable-neon-clobber-test --disable-programs --disable-postproc --disable-doc --disable-htmlpages --disable-manpages --disable-podpages --disable-txtpages --disable-static --disable-sndio --disable-schannel --disable-securetransport --disable-xlib --disable-cuda --disable-cuvid --disable-nvenc --disable-vaapi --disable-vdpau --disable-videotoolbox --disable-audiotoolbox --disable-appkit --disable-alsa --disable-cuda --disable-cuvid --disable-nvenc --disable-vaapi --disable-vdpau --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-gmp --enable-gnutls --enable-libmp3lame --enable-libass --enable-iconv --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libxml2 --enable-libopencore-amrnb --enable-libshine --enable-libspeex --enable-libwavpack --enable-libkvazaar --enable-libx264 --enable-gpl --enable-libxvid --enable-gpl --enable-libx265 --enable-gpl --enable-libvidstab --enable-gpl --enable-libilbc --enable-libopus --enable-libsnappy --enable-libsoxr --enable-libaom --enable-libtwolame --disable-sdl2 --enable-libvo-amrwbenc --enable-zlib --enable-mediacodec I/mobile-ffmpeg(10630): libavutil 56. 55.100 / 56. 55.100 I/mobile-ffmpeg(10630): libavcodec 58. 96.100 / 58. 96.100 I/mobile-ffmpeg(10630): libavformat 58. 48.100 / 58. 48.100 I/mobile-ffmpeg(10630): libavdevice 58. 11.101 / 58. 11.101 I/mobile-ffmpeg(10630): libavfilter 7. 87.100 / 7. 87.100 I/mobile-ffmpeg(10630): libswscale 5. 8.100 / 5. 8.100 I/mobile-ffmpeg(10630): libswresample 3. 8.100 / 3. 8.100 I/mobile-ffmpeg(10630): Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/data/user/0/com.terrant/app_flutter/traffic.mp4': I/mobile-ffmpeg(10630): Metadata: I/mobile-ffmpeg(10630): major_brand : I/mobile-ffmpeg(10630): qt
I/mobile-ffmpeg(10630): I/mobile-ffmpeg(10630): minor_version : I/mobile-ffmpeg(10630): 0 I/mobile-ffmpeg(10630): I/mobile-ffmpeg(10630): compatible_brands: I/mobile-ffmpeg(10630): qt
I/mobile-ffmpeg(10630): I/mobile-ffmpeg(10630): creation_time : I/mobile-ffmpeg(10630): 2021-09-06T14:35:31.000000Z I/mobile-ffmpeg(10630): I/mobile-ffmpeg(10630): Duration: D/flutter-ffmpeg(10630): FFmpeg exited with rc: 1 I/mobile-ffmpeg(10630): 00:00:13.26 I/mobile-ffmpeg(10630): , start: I/mobile-ffmpeg(10630): 0.000000 I/mobile-ffmpeg(10630): , bitrate: I/mobile-ffmpeg(10630): 2321 kb/s I/mobile-ffmpeg(10630): I/mobile-ffmpeg(10630): Stream #0:0 I/mobile-ffmpeg(10630): (und) I/mobile-ffmpeg(10630): : Video: h264 (avc1 / 0x31637661), yuv420p(tv, bt709), 1280x720 [SAR 1:1 DAR 16:9], 2318 kb/s I/mobile-ffmpeg(10630): , I/mobile-ffmpeg(10630): 23.98 fps, I/mobile-ffmpeg(10630): 23.98 tbr, I/mobile-ffmpeg(10630): 24k tbn, I/mobile-ffmpeg(10630): 48k tbc I/mobile-ffmpeg(10630): (default) I/mobile-ffmpeg(10630): I/mobile-ffmpeg(10630): Metadata: I/mobile-ffmpeg(10630): creation_time : I/mobile-ffmpeg(10630): 2021-09-06T14:35:31.000000Z I/mobile-ffmpeg(10630): I/mobile-ffmpeg(10630): handler_name : I/mobile-ffmpeg(10630): Core Media Video I/mobile-ffmpeg(10630): I/mobile-ffmpeg(10630): encoder : I/mobile-ffmpeg(10630): H.264 I/mobile-ffmpeg(10630): I/mobile-ffmpeg(10630): Output #0, mp3, to '/data/user/0/com.terrant/app_flutter/audio.mp3': E/mobile-ffmpeg(10630): Output file #0 does not contain any stream

[tanersener]

It seems like your file doesn't include an audio stream. It includes only the following h264 video stream inside.

Video: h264 (avc1 / 0x31637661), yuv420p(tv, bt709), 1280x720 [SAR 1:1 DAR 16:9], 2318 kb/s

[tanersener]

I mean your input file (.mp4) doesn't include any audio. There is no data to convert. Creating an empty output file doesn't change anything. Your problem is in the input.

[michalkubizna]

Thank you so much. That worked.