Merge commit '701966730ce10290fd49c5ccedd73f505680f764'

* commit '701966730ce10290fd49c5ccedd73f505680f764':
  vmd: drop incomplete chunks and spurious samples

Conflicts:
	libavcodec/vmdav.c

2 of the changes are replaced by assert0s, as they should
be impossible.
The actual bug is likely caused by a invalid block_align
which is checked for and thus impossible in ffmpeg.

Merged-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/vmdav.c

@@ -43,6 +43,7 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include "libavutil/avassert.h"
 #include "libavutil/channel_layout.h"
 #include "libavutil/common.h"
 #include "libavutil/intreadwrite.h"
@@ -588,6 +589,9 @@ static int vmdaudio_decode_frame(AVCodecContext *avctx, void *data,
     /* ensure output buffer is large enough */
     audio_chunks = buf_size / s->chunk_size;
 
+    /* drop incomplete chunks */
+    buf_size     = audio_chunks * s->chunk_size;
+
     /* get output buffer */
     frame->nb_samples = ((silent_chunks + audio_chunks) * avctx->block_align) /
                         avctx->channels;
@@ -599,6 +603,8 @@ static int vmdaudio_decode_frame(AVCodecContext *avctx, void *data,
     /* decode silent chunks */
     if (silent_chunks > 0) {
         int silent_size = avctx->block_align * silent_chunks;
+        av_assert0(avctx->block_align * silent_chunks <= frame->nb_samples * avctx->channels);
+
         if (s->out_bps == 2) {
             memset(output_samples_s16, 0x00, silent_size * 2);
             output_samples_s16 += silent_size;
@@ -611,6 +617,7 @@ static int vmdaudio_decode_frame(AVCodecContext *avctx, void *data,
     /* decode audio chunks */
     if (audio_chunks > 0) {
         buf_end = buf + buf_size;
+        av_assert0((buf_size & (avctx->channels > 1)) == 0);
         while (buf_end - buf >= s->chunk_size) {
             if (s->out_bps == 2) {
                 decode_audio_s16(output_samples_s16, buf, s->chunk_size,