lavf: add raw AVS2 demuxer

Signed-off-by: hwren <hwrenx@126.com>
Signed-off-by: Steven Liu <lq@chinaffmpeg.org>

libavformat/Makefile

@@ -115,6 +115,7 @@ OBJS-$(CONFIG_AVI_MUXER)                 += avienc.o mpegtsenc.o avlanguage.o ra
 OBJS-$(CONFIG_AVM2_MUXER)                += swfenc.o swf.o
 OBJS-$(CONFIG_AVR_DEMUXER)               += avr.o pcm.o
 OBJS-$(CONFIG_AVS_DEMUXER)               += avs.o voc_packet.o vocdec.o voc.o
+OBJS-$(CONFIG_AVS2_DEMUXER)              += davs2.o rawdec.o
 OBJS-$(CONFIG_AVS2_MUXER)                += rawenc.o
 OBJS-$(CONFIG_BETHSOFTVID_DEMUXER)       += bethsoftvid.o
 OBJS-$(CONFIG_BFI_DEMUXER)               += bfi.o

libavformat/allformats.c

@@ -76,6 +76,7 @@ extern AVInputFormat  ff_avisynth_demuxer;
 extern AVOutputFormat ff_avm2_muxer;
 extern AVInputFormat  ff_avr_demuxer;
 extern AVInputFormat  ff_avs_demuxer;
+extern AVInputFormat  ff_avs2_demuxer;
 extern AVOutputFormat ff_avs2_muxer;
 extern AVInputFormat  ff_bethsoftvid_demuxer;
 extern AVInputFormat  ff_bfi_demuxer;

libavformat/davs2.c

+/*
+ * AVS2 video stream probe.
+ *
+ * Copyright (C) 2018 Huiwen Ren, <hwrenx@126.com>
+ *
+ * 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 "libavcodec/internal.h"
+#include "libavutil/intreadwrite.h"
+
+#define ISSQH(x)  ((x) == 0xB0 )
+#define ISEND(x)  ((x) == 0xB1 )
+#define ISPIC(x)  ((x) == 0xB3 || (x) == 0xB6)
+#define ISUNIT(x) ( ISSQH(x) || ISEND(x) || (x) == 0xB2 || ISPIC(x) || (x) == 0xB5 || (x) == 0xB7 )
+#define ISAVS2(x) ((x) == 0x20 || (x) == 0x22 || (x) == 0x30 || (x) == 0x32 )
+
+static int avs2_probe(AVProbeData *p)
+{
+    if (AV_RB32(p->buf) != 0x1B0){
+        return 0;
+    }
+    uint32_t code= -1, hds=0, pic=0, seq=0;
+    uint8_t state=0;
+    const uint8_t *ptr = p->buf, *end = p->buf + p->buf_size, *sqb=0;
+
+    while (ptr < end) {
+        ptr = avpriv_find_start_code(ptr, end, &code);
+        state = code & 0xFF;
+        if ((code & 0xffffff00) == 0x100) {
+            if (ISUNIT(state)) {
+                if (sqb && !hds) {
+                    hds = ptr - sqb;
+                }
+                if (ISSQH(state)) {
+                    if (!ISAVS2(*ptr))
+                        return 0;
+                    sqb = ptr;
+                    seq++;
+                } else if (ISPIC(state)) {
+                    pic++;
+                } else if (ISEND(state)) {
+                    break;
+                }
+            }
+        }
+    }
+    if (seq && hds >= 21 && pic){
+        return AVPROBE_SCORE_EXTENSION + 2; // more than cavs
+    }
+
+    return 0;
+}
+
+FF_DEF_RAWVIDEO_DEMUXER(avs2, "raw AVS2-P2/IEEE1857.4", avs2_probe, "avs,avs2", AV_CODEC_ID_AVS2)