[FFmpeg-devel] [PATCH 3/7] CrystalHD: Handle different h.264 MBAFF packing.

[Philip Langdale]

I found another MBAFF sample where the input:output pattern is
the same as mpeg2 and vc1 (fieldpair input, individual field output).
While I'm not sure how you can output individual fields from MBAFF,
if I apply the mpeg2/vc1 handling to this file, it plays correctly.

So, this changes the detection algorithm to handle the known cases.

Signed-off-by: Philip Langdale <philipl at overt.org>
---
 libavcodec/crystalhd.c |   79 +++++++++++++++++++++++++----------------------
 1 files changed, 42 insertions(+), 37 deletions(-)

diff --git a/libavcodec/crystalhd.c b/libavcodec/crystalhd.c
index 3f66b96..95fe931 100644
--- a/libavcodec/crystalhd.c
+++ b/libavcodec/crystalhd.c
@@ -102,10 +102,11 @@
  ****************************************************************************/
 
 typedef enum {
-    RET_ERROR          = -1,
-    RET_OK             = 0,
-    RET_COPY_AGAIN     = 1,
-    RET_SKIP_NEXT_COPY = 2,
+    RET_ERROR           = -1,
+    RET_OK              = 0,
+    RET_COPY_AGAIN      = 1,
+    RET_SKIP_NEXT_COPY  = 2,
+    RET_COPY_NEXT_FIELD = 3,
 } CopyRet;
 
 typedef struct OpaqueList {
@@ -624,7 +625,13 @@ static inline CopyRet copy_frame(AVCodecContext *avctx,
         return RET_SKIP_NEXT_COPY;
     }
 
-    return RET_OK;
+    /*
+     * Testing has shown that in all cases where we don't want to return the
+     * full frame immediately, VDEC_FLAG_UNKNOWN_SRC is set.
+     */
+    return priv->need_second_field &&
+           !(output->PicInfo.flags & VDEC_FLAG_UNKNOWN_SRC) ?
+           RET_COPY_NEXT_FIELD : RET_OK;
 }
 
 
@@ -806,40 +813,38 @@ static int decode(AVCodecContext *avctx, void *data, int *data_size, AVPacket *a
 
     do {
         rec_ret = receive_frame(avctx, data, data_size, 0);
-        if (rec_ret == 0 && *data_size == 0) {
-            if (avctx->codec->id == CODEC_ID_H264) {
-                /*
-                 * This case is for when the encoded fields are stored
-                 * separately and we get a separate avpkt for each one. To keep
-                 * the pipeline stable, we should return nothing and wait for
-                 * the next time round to grab the second field.
-                 * H.264 PAFF is an example of this.
-                 */
-                av_log(avctx, AV_LOG_VERBOSE, "Returning after first field.\n");
-                avctx->has_b_frames--;
-            } else {
-                /*
-                 * This case is for when the encoded fields are stored in a
-                 * single avpkt but the hardware returns then separately. Unless
-                 * we grab the second field before returning, we'll slip another
-                 * frame in the pipeline and if that happens a lot, we're sunk.
-                 * So we have to get that second field now.
-                 * Interlaced mpeg2 and vc1 are examples of this.
-                 */
-                av_log(avctx, AV_LOG_VERBOSE, "Trying to get second field.\n");
-                while (1) {
-                    usleep(priv->decode_wait);
-                    ret = DtsGetDriverStatus(dev, &decoder_status);
-                    if (ret == BC_STS_SUCCESS &&
-                        decoder_status.ReadyListCount > 0) {
-                        rec_ret = receive_frame(avctx, data, data_size, 1);
-                        if ((rec_ret == 0 && *data_size > 0) ||
-                            rec_ret == RET_ERROR)
-                            break;
-                    }
+        if (rec_ret == RET_OK && *data_size == 0) {
+            /*
+             * This case is for when the encoded fields are stored
+             * separately and we get a separate avpkt for each one. To keep
+             * the pipeline stable, we should return nothing and wait for
+             * the next time round to grab the second field.
+             * H.264 PAFF is an example of this.
+             */
+            av_log(avctx, AV_LOG_VERBOSE, "Returning after first field.\n");
+            avctx->has_b_frames--;
+        } else if (rec_ret == RET_COPY_NEXT_FIELD) {
+            /*
+             * This case is for when the encoded fields are stored in a
+             * single avpkt but the hardware returns then separately. Unless
+             * we grab the second field before returning, we'll slip another
+             * frame in the pipeline and if that happens a lot, we're sunk.
+             * So we have to get that second field now.
+             * Interlaced mpeg2 and vc1 are examples of this.
+             */
+            av_log(avctx, AV_LOG_VERBOSE, "Trying to get second field.\n");
+            while (1) {
+                usleep(priv->decode_wait);
+                ret = DtsGetDriverStatus(dev, &decoder_status);
+                if (ret == BC_STS_SUCCESS &&
+                    decoder_status.ReadyListCount > 0) {
+                    rec_ret = receive_frame(avctx, data, data_size, 1);
+                    if ((rec_ret == RET_OK && *data_size > 0) ||
+                        rec_ret == RET_ERROR)
+                        break;
                 }
-                av_log(avctx, AV_LOG_VERBOSE, "CrystalHD: Got second field.\n");
             }
+            av_log(avctx, AV_LOG_VERBOSE, "CrystalHD: Got second field.\n");
         } else if (rec_ret == RET_SKIP_NEXT_COPY) {
             /*
              * Two input packets got turned into a field pair. Gawd.
-- 
1.7.1