Fix bug caused by difference in stride and picture width.

When a frame is allocated using libschroedinger routines, the frame data size
does not match the actual frame size if the width is not a multiple of 16. So
we cannot do a straightforward memcpy of the frame returned by libschroedinger
into the FFmpeg picture as the stride differs from the width.

Fix this bug by allocating for the libschroedinger frame with the dimensions
in AVCodecContext within libavcodec and passing the frame to libschroedinger.

patch by Anuradha Suraparaju, anuradha rd.bbc.co uk

Originally committed as revision 19653 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/libschroedinger.c

@@ -77,3 +77,56 @@ int ff_get_schro_frame_format (SchroChromaFormat schro_pix_fmt,
     }
     return -1;
 }
+
+static void FreeSchroFrame(SchroFrame *frame, void *priv)
+{
+    AVPicture *p_pic = priv;
+
+    if (!p_pic)
+        return;
+
+    avpicture_free(p_pic);
+    av_freep(&p_pic);
+}
+
+SchroFrame *ff_create_schro_frame(AVCodecContext *avccontext,
+                                  SchroFrameFormat schro_frame_fmt)
+{
+    AVPicture *p_pic;
+    SchroFrame *p_frame;
+    int y_width, uv_width;
+    int y_height, uv_height;
+    int i;
+
+    y_width   = avccontext->width;
+    y_height  = avccontext->height;
+    uv_width  = y_width  >> (SCHRO_FRAME_FORMAT_H_SHIFT(schro_frame_fmt));
+    uv_height = y_height >> (SCHRO_FRAME_FORMAT_V_SHIFT(schro_frame_fmt));
+
+    p_pic = av_mallocz(sizeof(AVPicture));
+    avpicture_alloc(p_pic, avccontext->pix_fmt, y_width, y_height);
+
+    p_frame         = schro_frame_new();
+    p_frame->format = schro_frame_fmt;
+    p_frame->width  = y_width;
+    p_frame->height = y_height;
+    schro_frame_set_free_callback(p_frame, FreeSchroFrame, (void *)p_pic);
+
+    for (i = 0; i < 3; ++i) {
+        p_frame->components[i].width  = i ? uv_width : y_width;
+        p_frame->components[i].stride = p_pic->linesize[i];
+        p_frame->components[i].height = i ? uv_height : y_height;
+        p_frame->components[i].length =
+                 p_frame->components[i].stride * p_frame->components[i].height;
+        p_frame->components[i].data   = p_pic->data[i];
+
+        if (i) {
+            p_frame->components[i].v_shift =
+                SCHRO_FRAME_FORMAT_V_SHIFT(p_frame->format);
+            p_frame->components[i].h_shift =
+                SCHRO_FRAME_FORMAT_H_SHIFT(p_frame->format);
+        }
+    }
+
+    return p_frame;
+}

libavcodec/libschroedinger.h

@@ -53,4 +53,11 @@ SchroVideoFormatEnum ff_get_schro_video_format_preset (AVCodecContext *avccontex
 int ff_get_schro_frame_format(SchroChromaFormat schro_chroma_fmt,
                               SchroFrameFormat  *schro_frame_fmt);
 
+/**
+* Create a Schro frame based on the dimensions and frame format
+* passed. Returns a pointer to a frame on success, NULL on failure.
+*/
+SchroFrame *ff_create_schro_frame(AVCodecContext *avccontext,
+                                  SchroFrameFormat schro_frame_fmt);
+
 #endif /* AVCODEC_LIBSCHROEDINGER_H */

libavcodec/libschroedingerdec.c

@@ -256,11 +256,8 @@ static int libschroedinger_decode_frame(AVCodecContext *avccontext,
 
             case SCHRO_DECODER_NEED_FRAME:
                 /* Decoder needs a frame - create one and push it in. */
-
-                frame = schro_frame_new_and_alloc(NULL,
-                                                  p_schro_params->frame_format,
-                                                  format->width,
-                                                  format->height);
+                frame = ff_create_schro_frame(avccontext,
+                                              p_schro_params->frame_format);
                 schro_decoder_add_output_picture(decoder, frame);
                 break;
 

libavcodec/libschroedingerenc.c

@@ -223,15 +223,13 @@ static SchroFrame *libschroedinger_frame_from_data(AVCodecContext *avccontext,
     /* Input line size may differ from what the codec supports. Especially
      * when transcoding from one format to another. So use avpicture_layout
      * to copy the frame. */
-    in_frame = schro_frame_new_and_alloc(NULL,
-                                         p_schro_params->frame_format,
-                                         p_schro_params->format->width,
-                                         p_schro_params->format->height);
-
-    avpicture_layout((AVPicture *)in_data, avccontext->pix_fmt,
-                     avccontext->width, avccontext->height,
-                     in_frame->components[0].data,
-                     p_schro_params->frame_size);
+    in_frame = ff_create_schro_frame(avccontext, p_schro_params->frame_format);
+
+    if (in_frame)
+        avpicture_layout((AVPicture *)in_data, avccontext->pix_fmt,
+                          avccontext->width, avccontext->height,
+                          in_frame->components[0].data,
+                          p_schro_params->frame_size);
 
     return in_frame;
 }