Support broken v210 files with 64 byte padding.

Fixes ticket #743.

Reviewed-by: Paul B Mahol

libavcodec/v210dec.c

@@ -86,6 +86,18 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
         stride = aligned_width * 8 / 3;
     }
 
+    if (avpkt->size < stride * avctx->height) {
+        if ((((avctx->width + 23) / 24) * 24 * 8) / 3 * avctx->height == avpkt->size) {
+            stride = avpkt->size / avctx->height;
+            if (!s->stride_warning_shown)
+                av_log(avctx, AV_LOG_WARNING, "Broken v210 with too small padding (64 byte) detected\n");
+            s->stride_warning_shown = 1;
+        } else {
+            av_log(avctx, AV_LOG_ERROR, "packet too small\n");
+            return -1;
+        }
+    }
+
     aligned_input = !((uintptr_t)psrc & 0xf) && !(stride & 0xf);
     if (aligned_input != s->aligned_input) {
         s->aligned_input = aligned_input;
@@ -96,11 +108,6 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *data_size,
     if (pic->data[0])
         avctx->release_buffer(avctx, pic);
 
-    if (avpkt->size < stride * avctx->height) {
-        av_log(avctx, AV_LOG_ERROR, "packet too small\n");
-        return -1;
-    }
-
     pic->reference = 0;
     if (avctx->get_buffer(avctx, pic) < 0)
         return -1;

libavcodec/v210dec.h

@@ -26,6 +26,7 @@ typedef struct {
     AVClass *av_class;
     int custom_stride;
     int aligned_input;
+    int stride_warning_shown;
     void (*unpack_frame)(const uint32_t *src, uint16_t *y, uint16_t *u, uint16_t *v, int width);
 } V210DecContext;