https://bugs.gentoo.org/951199

Backport of [1] plus a chunk from [2] for another anim_movie.cc issue.

[1] https://projects.blender.org/blender/blender/commit/b1ca2f09dba5c4a6d21806ab913a2374bf7b3b8f
[2] https://projects.blender.org/blender/blender/pulls/121947
--- a/extern/audaspace/plugins/ffmpeg/FFMPEGReader.cpp
+++ b/extern/audaspace/plugins/ffmpeg/FFMPEGReader.cpp
@@ -28,7 +28,12 @@
 AUD_NAMESPACE_BEGIN
 
+/* FFmpeg < 4.0 */
 #if LIBAVCODEC_VERSION_MAJOR < 58
 #define FFMPEG_OLD_CODE
 #endif
+/* FFmpeg < 5.0 */
+#if LIBAVCODEC_VERSION_MAJOR < 59
+#define FFMPEG_OLD_CH_LAYOUT
+#endif
 
 SampleFormat FFMPEGReader::convertSampleFormat(AVSampleFormat format)
@@ -113,5 +118,11 @@
 			break;
 
-		int data_size = av_samples_get_buffer_size(nullptr, m_codecCtx->channels, m_frame->nb_samples, m_codecCtx->sample_fmt, 1);
+		#ifdef FFMPEG_OLD_CH_LAYOUT
+			int channels = m_codecCtx->channels;
+		#else
+			int channels = m_codecCtx->ch_layout.nb_channels;
+		#endif
+
+		int data_size = av_samples_get_buffer_size(nullptr, channels, m_frame->nb_samples, m_codecCtx->sample_fmt, 1);
 
 		if(buf_size - buf_pos < data_size)
@@ -123,10 +134,10 @@
 		if(m_tointerleave)
 		{
-			int single_size = data_size / m_codecCtx->channels / m_frame->nb_samples;
-			for(int channel = 0; channel < m_codecCtx->channels; channel++)
+			int single_size = data_size / channels / m_frame->nb_samples;
+			for(int channel = 0; channel < channels; channel++)
 			{
 				for(int i = 0; i < m_frame->nb_samples; i++)
 				{
-					std::memcpy(((data_t*)buffer.getBuffer()) + buf_pos + ((m_codecCtx->channels * i) + channel) * single_size,
+					std::memcpy(((data_t*)buffer.getBuffer()) + buf_pos + ((channels * i) + channel) * single_size,
 						   m_frame->data[channel] + i * single_size, single_size);
 				}
@@ -208,5 +219,10 @@
 		AUD_THROW(FileException, "File couldn't be read, ffmpeg codec couldn't be opened.");
 
-	m_specs.channels = (Channels) m_codecCtx->channels;
+	#ifdef FFMPEG_OLD_CH_LAYOUT
+		int channels = m_codecCtx->channels;
+	#else
+		int channels = m_codecCtx->ch_layout.nb_channels;
+	#endif
+	m_specs.channels = (Channels) channels;
 	m_tointerleave = av_sample_fmt_is_planar(m_codecCtx->sample_fmt);
 
@@ -346,5 +362,10 @@
 			info.specs.format = convertSampleFormat(m_formatCtx->streams[i]->codec->sample_fmt);
 #else
-			info.specs.channels = Channels(m_formatCtx->streams[i]->codecpar->channels);
+			#ifdef FFMPEG_OLD_CH_LAYOUT
+				int channels = m_formatCtx->streams[i]->codecpar->channels;
+			#else
+				int channels = m_formatCtx->streams[i]->codecpar->ch_layout.nb_channels;
+			#endif
+			info.specs.channels = Channels(channels);
 			info.specs.rate = m_formatCtx->streams[i]->codecpar->sample_rate;
 			info.specs.format = convertSampleFormat(AVSampleFormat(m_formatCtx->streams[i]->codecpar->format));
--- a/extern/audaspace/plugins/ffmpeg/FFMPEGWriter.cpp
+++ b/extern/audaspace/plugins/ffmpeg/FFMPEGWriter.cpp
@@ -31,7 +31,12 @@
 AUD_NAMESPACE_BEGIN
 
+/* FFmpeg < 4.0 */
 #if LIBAVCODEC_VERSION_MAJOR < 58
 #define FFMPEG_OLD_CODE
 #endif
+/* FFmpeg < 5.0 */
+#if LIBAVCODEC_VERSION_MAJOR < 59
+#define FFMPEG_OLD_CH_LAYOUT
+#endif
 
 void FFMPEGWriter::encode()
@@ -78,6 +83,11 @@
 	m_frame->nb_samples = m_input_samples;
 	m_frame->format = m_codecCtx->sample_fmt;
+#ifdef FFMPEG_OLD_CH_LAYOUT
 	m_frame->channel_layout = m_codecCtx->channel_layout;
 	m_frame->channels = m_specs.channels;
+#else
+	if(av_channel_layout_copy(&m_frame->ch_layout, &m_codecCtx->ch_layout) < 0)
+		AUD_THROW(FileException, "File couldn't be written, couldn't copy audio channel layout.");
+#endif
 
 	if(avcodec_fill_audio_frame(m_frame, m_specs.channels, m_codecCtx->sample_fmt, reinterpret_cast<data_t*>(data), m_input_buffer.getSize(), 0) < 0)
@@ -406,6 +416,11 @@
 		m_codecCtx->codec_type = AVMEDIA_TYPE_AUDIO;
 		m_codecCtx->bit_rate = bitrate;
+#ifdef FFMPEG_OLD_CH_LAYOUT
 		m_codecCtx->channel_layout = channel_layout;
 		m_codecCtx->channels = m_specs.channels;
+#else
+		av_channel_layout_uninit(&m_codecCtx->ch_layout);
+		av_channel_layout_from_mask(&m_codecCtx->ch_layout, channel_layout);
+#endif
 		m_stream->time_base.num = m_codecCtx->time_base.num = 1;
 		m_stream->time_base.den = m_codecCtx->time_base.den = m_codecCtx->sample_rate;
--- a/intern/ffmpeg/ffmpeg_compat.h
+++ b/intern/ffmpeg/ffmpeg_compat.h
@@ -41,4 +41,11 @@
 #endif
 
+#if LIBAVUTIL_VERSION_INT < AV_VERSION_INT(58, 29, 100)
+/* In ffmpeg 6.1 usage of the "key_frame" variable from "AVFrame" has been deprecated.
+ * used the new method to query for the "AV_FRAME_FLAG_KEY" flag instead.
+ */
+#  define FFMPEG_OLD_KEY_FRAME_QUERY_METHOD
+#endif
+
 #if (LIBAVFORMAT_VERSION_MAJOR < 59)
 /* For versions older than ffmpeg 5.0, use the old channel layout variables.
--- a/source/blender/imbuf/intern/anim_movie.cc
+++ b/source/blender/imbuf/intern/anim_movie.cc
@@ -657,5 +657,9 @@
   anim->cur_pts = av_get_pts_from_frame(anim->pFrame);
 
+#  ifdef FFMPEG_OLD_KEY_FRAME_QUERY_METHOD
   if (anim->pFrame->key_frame) {
+#  else
+  if (anim->pFrame->flags & AV_FRAME_FLAG_KEY) {
+#  endif
     anim->cur_key_frame_pts = anim->cur_pts;
   }
@@ -1036,9 +1040,8 @@
     AVFormatContext *format_ctx = anim->pFormatCtx;
 
-    if (format_ctx->iformat->read_seek2 || format_ctx->iformat->read_seek) {
-      ret = av_seek_frame(anim->pFormatCtx, anim->videoStream, seek_pos, AVSEEK_FLAG_BACKWARD);
-    }
-    else {
-      ret = ffmpeg_generic_seek_workaround(anim, &seek_pos, pts_to_search);
+    int ret = av_seek_frame(anim->pFormatCtx, anim->videoStream, seek_pos, AVSEEK_FLAG_BACKWARD);
+
+    if (ret < 0) {
+      ret = ffmpeg_generic_seek_workaround(anim, &seek_pos, pts_to_search);\
       av_log(anim->pFormatCtx,
              AV_LOG_DEBUG,