refactor(UBFFmpegVideoEncoder): Use avcodec_get_supported_config

FFmpeg 7.1 introduces avcodec_get_supported_config to query
available sample formats. It basically copies over sample_fmts,
but doing so directly is deprecated.

Author: Vekhir

src/podcast/ffmpeg/UBFFmpegVideoEncoder.cpp

@@ -448,7 +448,19 @@ bool UBFFmpegVideoEncoder::init()
         }
 
         c->bit_rate = 96000;
-        c->sample_fmt  = audioCodec->sample_fmts ? audioCodec->sample_fmts[0] : AV_SAMPLE_FMT_FLTP;// FLTP by default for AAC
+
+        const AVSampleFormat* sample_fmts;
+#if LIBAVCODEC_VERSION_INT < AV_VERSION_INT(61, 19, 100)
+        sample_fmts = audioCodec->sample_fmts;
+#else
+        int err = avcodec_get_supported_config(nullptr, audioCodec, AV_CODEC_CONFIG_SAMPLE_FORMAT, 0, (const void**)&sample_fmts, nullptr);
+        if (err) {
+            setLastErrorMessage("Could not get supported sample formats");
+            return false;
+        }
+#endif
+        c->sample_fmt  = sample_fmts ? sample_fmts[0] : AV_SAMPLE_FMT_FLTP;// FLTP by default for AAC
+
         c->sample_rate = mAudioSampleRate;
 
 #if LIBAVUTIL_VERSION_INT < AV_VERSION_INT(57, 25, 100)