Implement shared parsing of INFO tag in Canopus family

Add some bounds checking to CLLC; reduce HQX variable scoping,
add an error message.

libavcodec/Makefile

@@ -156,7 +156,7 @@ OBJS-$(CONFIG_CDXL_DECODER)            += cdxl.o
 OBJS-$(CONFIG_CINEPAK_DECODER)         += cinepak.o
 OBJS-$(CONFIG_CLJR_DECODER)            += cljrdec.o
 OBJS-$(CONFIG_CLJR_ENCODER)            += cljrenc.o
-OBJS-$(CONFIG_CLLC_DECODER)            += cllc.o
+OBJS-$(CONFIG_CLLC_DECODER)            += cllc.o canopus.o
 OBJS-$(CONFIG_COOK_DECODER)            += cook.o
 OBJS-$(CONFIG_COMFORTNOISE_DECODER)    += cngdec.o celp_filters.o
 OBJS-$(CONFIG_COMFORTNOISE_ENCODER)    += cngenc.o
@@ -232,7 +232,7 @@ OBJS-$(CONFIG_HEVC_DECODER)            += hevc.o hevc_mvs.o hevc_ps.o hevc_sei.o
                                           hevc_cabac.o hevc_refs.o hevcpred.o    \
                                           hevcdsp.o hevc_filter.o
 OBJS-$(CONFIG_HNM4_VIDEO_DECODER)      += hnm4video.o
-OBJS-$(CONFIG_HQX_DECODER)             += hqx.o hqxvlc.o hqxdsp.o
+OBJS-$(CONFIG_HQX_DECODER)             += hqx.o hqxvlc.o hqxdsp.o canopus.o
 OBJS-$(CONFIG_HUFFYUV_DECODER)         += huffyuv.o huffyuvdec.o
 OBJS-$(CONFIG_HUFFYUV_ENCODER)         += huffyuv.o huffyuvenc.o
 OBJS-$(CONFIG_IDCIN_DECODER)           += idcinvideo.o

libavcodec/canopus.c

@@ -0,0 +1,63 @@
+/*
+ * Canopus common routines
+ * Copyright (c) 2015 Vittorio Giovara <vittorio.giovara@gmail.com>
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <stdint.h>
+
+#include "libavutil/rational.h"
+
+#include "avcodec.h"
+#include "bytestream.h"
+#include "canopus.h"
+
+int ff_canopus_parse_info_tag(AVCodecContext *avctx,
+                              const uint8_t *src, size_t size)
+{
+    GetByteContext gbc;
+    int par_x, par_y, field_order;
+
+    bytestream2_init(&gbc, src, size);
+
+    /* Parse aspect ratio. */
+    bytestream2_skip(&gbc, 8); // unknown, 16 bits 1
+    par_x = bytestream2_get_le32(&gbc);
+    par_y = bytestream2_get_le32(&gbc);
+    if (par_x && par_y)
+        av_reduce(&avctx->sample_aspect_ratio.num,
+                  &avctx->sample_aspect_ratio.den,
+                  par_x, par_y, 255);
+
+    /* Short INFO tag (used in CLLC) has only AR data. */
+    if (size == 0x18)
+        return 0;
+
+    bytestream2_skip(&gbc, 16); // unknown RDRT tag
+
+    /* Parse FIEL tag. */
+    bytestream2_skip(&gbc, 8); // 'FIEL' and 4 bytes 0
+    field_order = bytestream2_get_le32(&gbc);
+    switch (field_order) {
+    case 0: avctx->field_order = AV_FIELD_TT; break;
+    case 1: avctx->field_order = AV_FIELD_BB; break;
+    case 2: avctx->field_order = AV_FIELD_PROGRESSIVE; break;
+    }
+
+    return 0;
+}

libavcodec/canopus.h

@@ -0,0 +1,32 @@
+/*
+ * Canopus common routines
+ * Copyright (c) 2015 Vittorio Giovara <vittorio.giovara@gmail.com>
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVCODEC_CANOPUS_H
+#define AVCODEC_CANOPUS_H
+
+#include <stdint.h>
+
+#include "avcodec.h"
+
+int ff_canopus_parse_info_tag(AVCodecContext *avctx,
+                              const uint8_t *src, size_t size);
+
+#endif /* AVCODEC_CANOPUS_H */

libavcodec/cllc.c

@@ -24,6 +24,7 @@
 
 #include "libavutil/intreadwrite.h"
 #include "bswapdsp.h"
+#include "canopus.h"
 #include "get_bits.h"
 #include "avcodec.h"
 #include "internal.h"
@@ -362,7 +363,11 @@ static int cllc_decode_frame(AVCodecContext *avctx, void *data,
     GetBitContext gb;
     int coding_type, ret;
 
-    /* Skip the INFO header if present */
+    if (avpkt->size < 4 + 4) {
+        av_log(avctx, AV_LOG_ERROR, "Frame is too small %d.\n", avpkt->size);
+        return AVERROR_INVALIDDATA;
+    }
+
     info_offset = 0;
     info_tag    = AV_RL32(src);
     if (info_tag == MKTAG('I', 'N', 'F', 'O')) {
@@ -373,11 +378,10 @@ static int cllc_decode_frame(AVCodecContext *avctx, void *data,
                    info_offset);
             return AVERROR_INVALIDDATA;
         }
+        ff_canopus_parse_info_tag(avctx, src + 8, info_offset);
 
         info_offset += 8;
         src         += info_offset;
-
-        av_log(avctx, AV_LOG_DEBUG, "Skipping INFO chunk.\n");
     }
 
     data_size = (avpkt->size - info_offset) & ~1;

libavcodec/hqx.c

@@ -24,6 +24,7 @@
 #include "libavutil/intreadwrite.h"
 
 #include "avcodec.h"
+#include "canopus.h"
 #include "get_bits.h"
 #include "internal.h"
 
@@ -405,29 +406,28 @@ static int hqx_decode_frame(AVCodecContext *avctx, void *data,
 {
     HQXContext *ctx = avctx->priv_data;
     uint8_t *src = avpkt->data;
-    uint32_t info_tag, info_offset;
+    uint32_t info_tag;
     int data_start;
     int i, ret;
 
-    if (avpkt->size < 8)
+    if (avpkt->size < 4 + 4) {
+        av_log(avctx, AV_LOG_ERROR, "Frame is too small %d.\n", avpkt->size);
         return AVERROR_INVALIDDATA;
+    }
 
-    /* Skip the INFO header if present */
-    info_offset = 0;
     info_tag    = AV_RL32(src);
     if (info_tag == MKTAG('I', 'N', 'F', 'O')) {
-        info_offset = AV_RL32(src + 4);
+        int info_offset = AV_RL32(src + 4);
         if (info_offset > UINT32_MAX - 8 || info_offset + 8 > avpkt->size) {
             av_log(avctx, AV_LOG_ERROR,
                    "Invalid INFO header offset: 0x%08"PRIX32" is too large.\n",
                    info_offset);
             return AVERROR_INVALIDDATA;
         }
+        ff_canopus_parse_info_tag(avctx, src + 8, info_offset);
 
         info_offset += 8;
         src         += info_offset;
-
-        av_log(avctx, AV_LOG_DEBUG, "Skipping INFO chunk.\n");
     }
 
     data_start     = src - avpkt->data;