[FFmpeg-devel] [PATCH]vc1 Autodetection

[Carl Eugen Hoyos]

On Monday 05 October 2015 03:53:32 am Michael Niedermayer wrote:
> On Sun, Oct 04, 2015 at 11:47:59PM +0200, Carl Eugen Hoyos wrote:
> > Hi!
> >
> > Attached is a patch implementing vc-1 autodetection.
> >
> > Please review, Carl Eugen
> >
> >  Makefile  |    2 -
> >  rawdec.c  |    4 ---
> >  vc1dec.c  |   71
> > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ version.h
> > |    2 -
> >  4 files changed, 73 insertions(+), 6 deletions(-)
>
> tools/probetest 100 100000
> ...
> testing size=65536
> Failure of vc1 probing code with score=51 type=1 p=DF0 size=65536

Slightly improved patch attached that passes probetest.

Please review, Carl Eugen
-------------- next part --------------
diff --git a/libavformat/Makefile b/libavformat/Makefile
index 2971912..d118019 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -440,7 +440,7 @@ OBJS-$(CONFIG_TTA_DEMUXER)               += tta.o apetag.o img2.o
 OBJS-$(CONFIG_TTY_DEMUXER)               += tty.o sauce.o
 OBJS-$(CONFIG_TXD_DEMUXER)               += txd.o
 OBJS-$(CONFIG_UNCODEDFRAMECRC_MUXER)     += uncodedframecrcenc.o framehash.o
-OBJS-$(CONFIG_VC1_DEMUXER)               += rawdec.o
+OBJS-$(CONFIG_VC1_DEMUXER)               += rawdec.o vc1dec.o
 OBJS-$(CONFIG_VC1_MUXER)                 += rawenc.o
 OBJS-$(CONFIG_VC1T_DEMUXER)              += vc1test.o
 OBJS-$(CONFIG_VC1T_MUXER)                += vc1testenc.o
diff --git a/libavformat/rawdec.c b/libavformat/rawdec.c
index 16fb221..7098ebd 100644
--- a/libavformat/rawdec.c
+++ b/libavformat/rawdec.c
@@ -205,7 +205,3 @@ static int mjpeg_probe(AVProbeData *p)
 
 FF_DEF_RAWVIDEO_DEMUXER2(mjpeg, "raw MJPEG video", mjpeg_probe, "mjpg,mjpeg,mpo", AV_CODEC_ID_MJPEG, AVFMT_GENERIC_INDEX|AVFMT_NOTIMESTAMPS)
 #endif
-
-#if CONFIG_VC1_DEMUXER
-FF_DEF_RAWVIDEO_DEMUXER2(vc1, "raw VC-1", NULL, "vc1", AV_CODEC_ID_VC1, AVFMT_GENERIC_INDEX|AVFMT_NOTIMESTAMPS)
-#endif
diff --git a/libavformat/vc1dec.c b/libavformat/vc1dec.c
index e69de29..33f8465 100644
--- a/libavformat/vc1dec.c
+++ b/libavformat/vc1dec.c
@@ -0,0 +1,81 @@
+/*
+ * VC-1 demuxer
+ * Copyright (c) 2015 Carl Eugen Hoyos
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "avformat.h"
+#include "rawdec.h"
+#include "libavutil/intreadwrite.h"
+#include "libavcodec/vc1_common.h"
+
+static int vc1_probe(AVProbeData *p)
+{
+    int seq = 0, entry = 0, frame = 0, i;
+
+    for (i = 0; i < p->buf_size + 5; i++) {
+        uint32_t code = AV_RB32(p->buf + i);
+        if ((code & 0xffffffe0) == 0x100) {
+            int type = code & 0x11f;
+            i += 4;
+            switch (type) {
+            case VC1_CODE_SEQHDR: {
+                int profile, level, chromaformat;
+                profile = (p->buf[i] & 0xc0) >> 6;
+                if (profile != PROFILE_ADVANCED) {
+                    seq = 0;
+                    continue;
+                }
+                level = (p->buf[i] & 0x38) >> 3;
+                if (level >= 5) {
+                    seq = 0;
+                    continue;
+                }
+                chromaformat = (p->buf[i] & 0x6) >> 1;
+                if (chromaformat != 1) {
+                    seq = 0;
+                    continue;
+                }
+                seq++;
+                i += 6;
+                break;
+            }
+            case VC1_CODE_ENTRYPOINT:
+                if (!seq)
+                    continue;
+                entry++;
+                i += 2;
+                break;
+            case VC1_CODE_FRAME:
+            case VC1_CODE_FIELD:
+            case VC1_CODE_SLICE:
+                if (seq && entry)
+                    frame++;
+                break;
+            }
+        }
+    }
+
+    if (frame > 1)
+        return AVPROBE_SCORE_EXTENSION / 2 + 1;
+    if (frame == 1)
+        return AVPROBE_SCORE_EXTENSION / 4;
+    return 0;
+}
+
+FF_DEF_RAWVIDEO_DEMUXER2(vc1, "raw VC-1", vc1_probe, "vc1", AV_CODEC_ID_VC1, AVFMT_GENERIC_INDEX|AVFMT_NOTIMESTAMPS)
diff --git a/libavformat/version.h b/libavformat/version.h
index f7a2e09..76e2f55 100644
--- a/libavformat/version.h
+++ b/libavformat/version.h
@@ -31,7 +31,7 @@
 
 #define LIBAVFORMAT_VERSION_MAJOR  57
 #define LIBAVFORMAT_VERSION_MINOR   3
-#define LIBAVFORMAT_VERSION_MICRO 100
+#define LIBAVFORMAT_VERSION_MICRO 101
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
                                                LIBAVFORMAT_VERSION_MINOR, \