indeo5: change AVCodecContext w/h when internal ones change.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/indeo5.c

@@ -797,6 +797,10 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
     if (ctx->frame.data[0])
         avctx->release_buffer(avctx, &ctx->frame);
 
+    if(   avctx->width  != ctx->planes[0].width
+       || avctx->height != ctx->planes[0].height)
+        avcodec_set_dimensions(avctx, ctx->planes[0].width, ctx->planes[0].height);
+
     ctx->frame.reference = 0;
     if (avctx->get_buffer(avctx, &ctx->frame) < 0) {
         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");