downgrade ffmpeg (fixes segfault & mono <-> stereo conversion bugs)

Dockerfile

@@ -23,9 +23,10 @@ RUN apk add --no-cache \
     gnutls-dev && \
     mkdir -p /ffmpeg/{ffmpeg_build,bin} && \
     cd /ffmpeg && \
-    wget -O ffmpeg-7.0.1.tar.bz2 https://ffmpeg.org/releases/ffmpeg-7.0.1.tar.bz2 && \
-    tar xjvf ffmpeg-7.0.1.tar.bz2 && \
-    cd ffmpeg-7.0.1 && \
+    export FFMPEG_VERSION=6.1.1 && \
+    wget -O ffmpeg-$FFMPEG_VERSION.tar.bz2 https://ffmpeg.org/releases/ffmpeg-$FFMPEG_VERSION.tar.bz2 && \
+    tar xjvf ffmpeg-$FFMPEG_VERSION.tar.bz2 && \
+    cd ffmpeg-$FFMPEG_VERSION && \
     PKG_CONFIG_PATH="/ffmpeg/ffmpeg_build/lib/pkgconfig" ./configure \
       --prefix="/ffmpeg/ffmpeg_build" \
       --pkg-config-flags="--static" \

README.md

@@ -41,9 +41,9 @@ You can change configuration using this environment variables:
 - [x] Remove old conversion results and input files that are older than 1 hour.
 - [x] Remove input file after transcoding it.
 - [x] Do not upload files directly, add download route with streaming instead.
+- [x] Conversion from OGG Opus mono to HE-AAC v1 Stereo outputs high-pitched crackling audio.
+- [x] Conversion from OGG Opus mono to AAC sometimes crashes the app with SIGSEGV (this can be seen more often with very short audio).
 - [ ] If FFmpeg fails, `send_error` won't be called - fix that.
 - [ ] Default errors are returned in plain text. Change it to the JSON.
-- [ ] Conversion from OGG Opus mono to HE-AAC v1 Stereo outputs high-pitched crackling audio.
-- [ ] Conversion from OGG Opus mono to AAC sometimes crashes the app with SIGSEGV (this can be seen more often with very short audio).
 - [ ] Docker image for `amd64` and `arm64` (currently only `amd64` is supported because `arm64` cross-compilation with QEMU is sloooooooooooowwwww...).
 - [ ] Tests!

src/transcoder.rs

@@ -70,6 +70,9 @@ impl Transcoder {
         encoder.set_rate(sample_rate);
         encoder.set_channel_layout(params.channel_layout);
 
+        #[cfg(not(feature = "ffmpeg_7_0"))]
+        encoder.set_channels(params.channel_layout.channels());
+
         encoder.set_format(
             codec
                 .formats()