From 2d6edb2b7ebc400d1a4fd5b95a30e4b4415b94f9 Mon Sep 17 00:00:00 2001
From: Anton Khirnov <anton@khirnov.net>
Date: Fri, 22 Mar 2013 08:20:27 +0100
Subject: [PATCH 1/2] lavc: extend / update the [coded_]{width,height} doxy

---
 libavcodec/avcodec.h | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h
index 316d30a656..84a685986b 100644
--- a/libavcodec/avcodec.h
+++ b/libavcodec/avcodec.h
@@ -1148,16 +1148,20 @@ typedef struct AVCodecContext {
     /**
      * picture width / height.
      * - encoding: MUST be set by user.
-     * - decoding: Set by libavcodec.
-     * Note: For compatibility it is possible to set this instead of
-     * coded_width/height before decoding.
+     * - decoding: May be set by the user before opening the decoder if known e.g.
+     *             from the container. Some decoders will require the dimensions
+     *             to be set by the caller. During decoding, the decoder may
+     *             overwrite those values as required.
      */
     int width, height;
 
     /**
-     * Bitstream width / height, may be different from width/height.
+     * Bitstream width / height, may be different from width/height e.g. when
+     * the decoded frame is cropped before being output.
      * - encoding: unused
-     * - decoding: Set by user before init if known. Codec should override / dynamically change if needed.
+     * - decoding: May be set by the user before opening the decoder if known
+     *             e.g. from the container. During decoding, the decoder may
+     *             overwrite those values as required.
      */
     int coded_width, coded_height;
 

From 9de9b828ef005dec37052548c195a6b4f18fc701 Mon Sep 17 00:00:00 2001
From: Anton Khirnov <anton@khirnov.net>
Date: Fri, 22 Mar 2013 07:59:10 +0100
Subject: [PATCH 2/2] lavc: don't overwrite display dimensions with coded
 dimensions.

---
 libavcodec/utils.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/utils.c b/libavcodec/utils.c
index 46486a2ff7..dfb2f541e7 100644
--- a/libavcodec/utils.c
+++ b/libavcodec/utils.c
@@ -905,7 +905,7 @@ int attribute_align_arg avcodec_open2(AVCodecContext *avctx, const AVCodec *code
     if ((ret = av_opt_set_dict(avctx, &tmp)) < 0)
         goto free_and_end;
 
-    if (avctx->coded_width && avctx->coded_height)
+    if (avctx->coded_width && avctx->coded_height && !avctx->width && !avctx->height)
         avcodec_set_dimensions(avctx, avctx->coded_width, avctx->coded_height);
     else if (avctx->width && avctx->height)
         avcodec_set_dimensions(avctx, avctx->width, avctx->height);