[libav-stable] vmd: drop incomplete chunks and spurious samples

Luca Barbato git at libav.org
Wed May 29 21:30:25 CEST 2013


Module: libav
Branch: master
Commit: 701966730ce10290fd49c5ccedd73f505680f764

Author:    Luca Barbato <lu_zero at gentoo.org>
Committer: Luca Barbato <lu_zero at gentoo.org>
Date:      Wed May 29 16:59:13 2013 +0200

vmd: drop incomplete chunks and spurious samples

Odd chunk size makes no sense for stereo and incomplete chunks are
not supported.

Reported-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable at libav.org

---

 libavcodec/vmdav.c |    8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/libavcodec/vmdav.c b/libavcodec/vmdav.c
index d7f43f0..3a0cbf9 100644
--- a/libavcodec/vmdav.c
+++ b/libavcodec/vmdav.c
@@ -586,6 +586,9 @@ 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;
@@ -598,7 +601,8 @@ static int vmdaudio_decode_frame(AVCodecContext *avctx, void *data,
 
     /* decode silent chunks */
     if (silent_chunks > 0) {
-        int silent_size = avctx->block_align * silent_chunks;
+        int silent_size = FFMIN(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;
@@ -610,7 +614,7 @@ static int vmdaudio_decode_frame(AVCodecContext *avctx, void *data,
 
     /* decode audio chunks */
     if (audio_chunks > 0) {
-        buf_end = buf + buf_size;
+        buf_end = buf + (buf_size & ~(avctx->channels > 1));
         while (buf + s->chunk_size <= buf_end) {
             if (s->out_bps == 2) {
                 decode_audio_s16(output_samples_s16, buf, s->chunk_size,



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