[vlc-devel] [PATCH 1/4] omxil: Pass extradata for WMV3 according to OMX specs

[Martin Storsjö]

Some OMX decoders that can handle WMV3 (such as the broadcom one
in raspberry pi) can handle the WMV3 extradata both in the original
form as in ASF, and in this format, while the one in Samsung Galaxy
S3 requires it to be in this format (as the OMX IL 1.2 specs specify).

This makes HW-accelerated WMV3 decoding work on Galaxy S3.

The code can be split out to a reusable function if/when the same
needs to be done elsewhere.
---
 modules/codec/omxil/omxil.c |   31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/modules/codec/omxil/omxil.c b/modules/codec/omxil/omxil.c
index c2426f8..7494c8a 100644
--- a/modules/codec/omxil/omxil.c
+++ b/modules/codec/omxil/omxil.c
@@ -1079,6 +1079,37 @@ loaded:
             p_header->pOutputPortPrivate = p_header->pBuffer;
             p_header->pBuffer = p_dec->fmt_in.p_extra;
         }
+        else if (p_dec->fmt_in.i_codec == VLC_CODEC_WMV3 &&
+                 p_dec->fmt_in.i_extra >= 4 &&
+                 p_header->nAllocLen >= 36)
+        {
+            int profile;
+            // According to OMX IL 1.2.0 spec (4.3.33.2), the codec config
+            // data for VC-1 Main/Simple (aka WMV3) is according to table 265
+            // in the VC-1 spec. Most of the fields are just set with placeholders
+            // (like framerate, hrd_buffer/rate).
+            static const uint8_t wmv3seq[] = {
+                0xff, 0xff, 0xff, 0xc5, // numframes=ffffff, marker byte
+                0x04, 0x00, 0x00, 0x00, // marker byte
+                0x00, 0x00, 0x00, 0x00, // struct C, almost equal to p_extra
+                0x00, 0x00, 0x00, 0x00, // struct A, vert size
+                0x00, 0x00, 0x00, 0x00, // struct A, horiz size
+                0x0c, 0x00, 0x00, 0x00, // marker byte
+                0xff, 0xff, 0x00, 0x80, // struct B, level=4, cbr=0, hrd_buffer=ffff
+                0xff, 0xff, 0x00, 0x00, // struct B, hrd_rate=ffff
+                0xff, 0xff, 0xff, 0xff, // struct B, framerate=ffffffff
+            };
+            p_header->nFilledLen = sizeof(wmv3seq);
+            memcpy(p_header->pBuffer, wmv3seq, p_header->nFilledLen);
+            // Struct C - almost equal to the extradata
+            memcpy(&p_header->pBuffer[8], p_dec->fmt_in.p_extra, 4);
+            // Expand profile from the highest 2 bits to the highest 4 bits
+            profile = p_header->pBuffer[8] >> 6;
+            p_header->pBuffer[8] = (p_header->pBuffer[8] & 0x0f) | (profile << 4);
+            // Fill in the height/width for struct A
+            SetDWLE(&p_header->pBuffer[12], p_dec->fmt_in.video.i_height);
+            SetDWLE(&p_header->pBuffer[16], p_dec->fmt_in.video.i_width);
+        }
         else
         {
             if(p_header->nFilledLen > p_header->nAllocLen)
-- 
1.7.10.4