--- src/FFmpegWriter.cpp.orig	2026-08-18 06:00:44 UTC
+++ src/FFmpegWriter.cpp
@@ -1142,19 +1142,30 @@ AVStream *FFmpegWriter::add_audio_stream() {
 #endif
 
 	// Set valid sample rate (or throw error)
-	if (codec->supported_samplerates) {
-		int i;
-		for (i = 0; codec->supported_samplerates[i] != 0; i++)
-			if (info.sample_rate == codec->supported_samplerates[i]) {
-				// Set the valid sample rate
-				c->sample_rate = info.sample_rate;
-				break;
-			}
-		if (codec->supported_samplerates[i] == 0)
-			throw InvalidSampleRate("An invalid sample rate was detected for this codec.", path);
-	} else
-		// Set sample rate
-		c->sample_rate = info.sample_rate;
+	// AVCodec.supported_samplerates removed in FFmpeg 9+
+	{
+		const int *supported_samplerates = NULL;
+#if LIBAVCODEC_VERSION_INT >= AV_VERSION_INT(61, 13, 100)
+		if (avcodec_get_supported_config(NULL, codec, AV_CODEC_CONFIG_SAMPLE_RATE, 0,
+						 (const void **)&supported_samplerates, NULL) < 0)
+			supported_samplerates = NULL;
+#else
+		supported_samplerates = codec->supported_samplerates;
+#endif
+		if (supported_samplerates) {
+			int i;
+			for (i = 0; supported_samplerates[i] != 0; i++)
+				if (info.sample_rate == supported_samplerates[i]) {
+					// Set the valid sample rate
+					c->sample_rate = info.sample_rate;
+					break;
+				}
+			if (supported_samplerates[i] == 0)
+				throw InvalidSampleRate("An invalid sample rate was detected for this codec.", path);
+		} else
+			// Set sample rate
+			c->sample_rate = info.sample_rate;
+	}
 
 	c->time_base = AVRational{1, c->sample_rate};
 	st->time_base = c->time_base;
@@ -1162,22 +1173,33 @@ AVStream *FFmpegWriter::add_audio_stream() {
 	uint64_t channel_layout = info.channel_layout;
 #if HAVE_CH_LAYOUT
 	// Set a valid number of channels (or throw error)
+	// AVCodec.ch_layouts removed in FFmpeg 9+
 	AVChannelLayout ch_layout;
 	av_channel_layout_from_mask(&ch_layout, info.channel_layout);
-	if (codec->ch_layouts) {
-		int i;
-		for (i = 0; av_channel_layout_check(&codec->ch_layouts[i]); i++)
-			if (av_channel_layout_compare(&ch_layout, &codec->ch_layouts[i])) {
-				// Set valid channel layout
-				av_channel_layout_copy(&c->ch_layout, &ch_layout);
-				break;
-			}
-		if (!av_channel_layout_check(&codec->ch_layouts[i]))
-			throw InvalidChannels("An invalid channel layout was detected (i.e. MONO / STEREO).", path);
-	} else
-		// Set valid channel layout
-		av_channel_layout_copy(&c->ch_layout, &ch_layout);
+	{
+		const AVChannelLayout *ch_layouts = NULL;
+#if LIBAVCODEC_VERSION_INT >= AV_VERSION_INT(61, 13, 100)
+		if (avcodec_get_supported_config(NULL, codec, AV_CODEC_CONFIG_CHANNEL_LAYOUT, 0,
+						 (const void **)&ch_layouts, NULL) < 0)
+			ch_layouts = NULL;
 #else
+		ch_layouts = codec->ch_layouts;
+#endif
+		if (ch_layouts) {
+			int i;
+			for (i = 0; av_channel_layout_check(&ch_layouts[i]); i++)
+				if (av_channel_layout_compare(&ch_layout, &ch_layouts[i])) {
+					// Set valid channel layout
+					av_channel_layout_copy(&c->ch_layout, &ch_layout);
+					break;
+				}
+			if (!av_channel_layout_check(&ch_layouts[i]))
+				throw InvalidChannels("An invalid channel layout was detected (i.e. MONO / STEREO).", path);
+		} else
+			// Set valid channel layout
+			av_channel_layout_copy(&c->ch_layout, &ch_layout);
+	}
+#else
 	// Set a valid number of channels (or throw error)
 	if (codec->channel_layouts) {
 		int i;
@@ -1195,11 +1217,22 @@ AVStream *FFmpegWriter::add_audio_stream() {
 #endif
 
 	// Choose a valid sample_fmt
-	if (codec->sample_fmts) {
-		for (int i = 0; codec->sample_fmts[i] != AV_SAMPLE_FMT_NONE; i++) {
-			// Set sample format to 1st valid format (and then exit loop)
-			c->sample_fmt = codec->sample_fmts[i];
-			break;
+	// AVCodec.sample_fmts removed in FFmpeg 9+
+	{
+		const enum AVSampleFormat *sample_fmts = NULL;
+#if LIBAVCODEC_VERSION_INT >= AV_VERSION_INT(61, 13, 100)
+		if (avcodec_get_supported_config(NULL, codec, AV_CODEC_CONFIG_SAMPLE_FORMAT, 0,
+						 (const void **)&sample_fmts, NULL) < 0)
+			sample_fmts = NULL;
+#else
+		sample_fmts = codec->sample_fmts;
+#endif
+		if (sample_fmts) {
+			for (int i = 0; sample_fmts[i] != AV_SAMPLE_FMT_NONE; i++) {
+				// Set sample format to 1st valid format (and then exit loop)
+				c->sample_fmt = sample_fmts[i];
+				break;
+			}
 		}
 	}
 	if (c->sample_fmt == AV_SAMPLE_FMT_NONE) {
@@ -1401,7 +1434,15 @@ AVStream *FFmpegWriter::add_video_stream() {
 #endif
 
 	// Find all supported pixel formats for this codec
-	const PixelFormat *supported_pixel_formats = codec->pix_fmts;
+	// AVCodec.pix_fmts removed in FFmpeg 9+
+	const PixelFormat *supported_pixel_formats = NULL;
+#if LIBAVCODEC_VERSION_INT >= AV_VERSION_INT(61, 13, 100)
+	if (avcodec_get_supported_config(NULL, codec, AV_CODEC_CONFIG_PIX_FORMAT, 0,
+					 (const void **)&supported_pixel_formats, NULL) < 0)
+		supported_pixel_formats = NULL;
+#else
+	supported_pixel_formats = codec->pix_fmts;
+#endif
 	while (supported_pixel_formats != NULL && *supported_pixel_formats != PIX_FMT_NONE) {
 		// Assign the 1st valid pixel format (if one is missing)
 		if (c->pix_fmt == PIX_FMT_NONE)