[FFmpeg-devel] [PATCH]lavf/shortendec: Autodetect raw Shorten streams.

[Carl Eugen Hoyos]

On Friday 02 October 2015 12:48:17 pm Paul B Mahol wrote:
> On 10/2/15, Carl Eugen Hoyos <cehoyos at ag.or.at> wrote:
> > Hi!
> >
> > Attached patch implements Shorten auto-detection.
> >
> > Please comment, Carl Eugen
>
> You do not check byte size

I thought both the safe bitstream reader and the minimal 
probe buffer size avoid an overread here.
Is that wrong?

> and not using init_get_bits8. 

Fixed, thank you!

New patch attached, Carl Eugen
-------------- next part --------------
diff --git a/libavformat/Makefile b/libavformat/Makefile
index 466da51..a9af797 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -403,7 +403,7 @@ OBJS-$(CONFIG_SDP_DEMUXER)               += rtsp.o
 OBJS-$(CONFIG_SDR2_DEMUXER)              += sdr2.o
 OBJS-$(CONFIG_SEGAFILM_DEMUXER)          += segafilm.o
 OBJS-$(CONFIG_SEGMENT_MUXER)             += segment.o
-OBJS-$(CONFIG_SHORTEN_DEMUXER)           += rawdec.o
+OBJS-$(CONFIG_SHORTEN_DEMUXER)           += shortendec.o rawdec.o
 OBJS-$(CONFIG_SIFF_DEMUXER)              += siff.o
 OBJS-$(CONFIG_SINGLEJPEG_MUXER)          += rawenc.o
 OBJS-$(CONFIG_SMACKER_DEMUXER)           += smacker.o
diff --git a/libavformat/rawdec.c b/libavformat/rawdec.c
index ef84d37..46ee21e 100644
--- a/libavformat/rawdec.c
+++ b/libavformat/rawdec.c
@@ -266,18 +266,6 @@ AVInputFormat ff_truehd_demuxer = {
 };
 #endif
 
-#if CONFIG_SHORTEN_DEMUXER
-AVInputFormat ff_shorten_demuxer = {
-    .name           = "shn",
-    .long_name      = NULL_IF_CONFIG_SMALL("raw Shorten"),
-    .read_header    = ff_raw_audio_read_header,
-    .read_packet    = ff_raw_read_partial_packet,
-    .flags          = AVFMT_NOBINSEARCH | AVFMT_NOGENSEARCH | AVFMT_NO_BYTE_SEEK|AVFMT_NOTIMESTAMPS,
-    .extensions     = "shn",
-    .raw_codec_id   = AV_CODEC_ID_SHORTEN,
-};
-#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/shortendec.c b/libavformat/shortendec.c
index e69de29..42fcdf7 100644
--- a/libavformat/shortendec.c
+++ b/libavformat/shortendec.c
@@ -0,0 +1,71 @@
+/*
+ * Shorten demuxer
+ * Copyright (c) 2001 Fabrice Bellard
+ * Copyright (c) 2005 Alex Beregszaszi
+ * 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 "libavcodec/golomb.h"
+
+static int shn_probe(AVProbeData *p)
+{
+    GetBitContext gb;
+    int version, internal_ftype, channels, blocksize;
+
+    if (AV_RB32(p->buf) != 0x616a6b67)
+        return 0;
+    version = p->buf[4];
+    if (init_get_bits8(&gb, p->buf + 5, p->buf_size - 5 - AV_INPUT_BUFFER_PADDING_SIZE) < 0)
+        return 0;
+    if (!version) {
+        internal_ftype = get_ur_golomb_shorten(&gb, 4);
+        channels = get_ur_golomb_shorten(&gb, 0);
+        blocksize = 256;
+    } else {
+        int k;
+        k = get_ur_golomb_shorten(&gb, 2);
+        internal_ftype = get_ur_golomb_shorten(&gb, k);
+        k = get_ur_golomb_shorten(&gb, 2);
+        channels = get_ur_golomb_shorten(&gb, k);
+        k = get_ur_golomb_shorten(&gb, 2);
+        blocksize = get_ur_golomb_shorten(&gb, k);
+    }
+
+    if (internal_ftype != 2 && internal_ftype != 3 && internal_ftype != 5)
+        return 0;
+    if (channels < 1 || channels > 8)
+        return 0;
+    if (blocksize < 1 || blocksize > 65535)
+        return 0;
+
+    return AVPROBE_SCORE_EXTENSION + 1;
+}
+
+AVInputFormat ff_shorten_demuxer = {
+    .name           = "shn",
+    .long_name      = NULL_IF_CONFIG_SMALL("raw Shorten"),
+    .read_probe     = shn_probe,
+    .read_header    = ff_raw_audio_read_header,
+    .read_packet    = ff_raw_read_partial_packet,
+    .flags          = AVFMT_NOBINSEARCH | AVFMT_NOGENSEARCH | AVFMT_NO_BYTE_SEEK | AVFMT_NOTIMESTAMPS,
+    .extensions     = "shn",
+    .raw_codec_id   = AV_CODEC_ID_SHORTEN,
+};
diff --git a/libavformat/version.h b/libavformat/version.h
index 4c60e50..b4c4d23 100644
--- a/libavformat/version.h
+++ b/libavformat/version.h
@@ -31,7 +31,7 @@
 
 #define LIBAVFORMAT_VERSION_MAJOR  57
 #define LIBAVFORMAT_VERSION_MINOR   2
-#define LIBAVFORMAT_VERSION_MICRO 102
+#define LIBAVFORMAT_VERSION_MICRO 103
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
                                                LIBAVFORMAT_VERSION_MINOR, \