decoder/ffmpeg: fix playback of planar PCM data

src/decoder/ffmpeg_decoder_plugin.c

@@ -236,12 +236,16 @@ time_to_ffmpeg(double t, const AVRational time_base)
 #if LIBAVCODEC_VERSION_INT >= AV_VERSION_INT(53,25,0)
 
 static void
-copy_interleave_frame2(uint8_t *dest, const uint8_t *const*src,
-		       unsigned nchannels, size_t plane_size)
+copy_interleave_frame2(uint8_t *dest, uint8_t **src,
+		       unsigned nframes, unsigned nchannels,
+		       unsigned sample_size)
 {
-	for (unsigned channel = 0; channel < nchannels; ++channel) {
-		memcpy(dest, src[channel], plane_size);
-		dest += plane_size;
+	for (unsigned frame = 0; frame < nframes; ++frame) {
+		for (unsigned channel = 0; channel < nchannels; ++channel) {
+			memcpy(dest, src[channel] + frame * sample_size,
+			       sample_size);
+			dest += sample_size;
+		}
 	}
 }
 
@@ -265,9 +269,10 @@ copy_interleave_frame(const AVCodecContext *codec_context,
 
 	if (av_sample_fmt_is_planar(codec_context->sample_fmt) &&
 	    codec_context->channels > 1) {
-		copy_interleave_frame2(buffer,
-				       (const uint8_t *const*)frame->extended_data,
-				       codec_context->channels, plane_size);
+		copy_interleave_frame2(buffer, frame->extended_data,
+				       frame->nb_samples,
+				       codec_context->channels,
+				       av_get_bytes_per_sample(codec_context->sample_fmt));
 	} else {
 		memcpy(buffer, frame->extended_data[0], data_size);
 	}