avcodec: add a Vorbis parser to get packet duration

This also allows for removing some of the Vorbis-related hacks.

1 files changed, 68 insertions, 0 deletions

diff --git a/libavcodec/vorbis_parser.h b/libavcodec/vorbis_parser.h
new file mode 100644
index 0000000000..480a918f7b
--- /dev/null
+++ b/libavcodec/vorbis_parser.h
@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2012 Justin Ruggles
+ *
+ * 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
+ */
+
+/**
+ * @file
+ * Vorbis audio parser
+ *
+ * Determines the duration for each packet.
+ */
+
+#ifndef AVCODEC_VORBIS_PARSER_H
+#define AVCODEC_VORBIS_PARSER_H
+
+#include "avcodec.h"
+
+typedef struct VorbisParseContext {
+    AVCodecContext *avctx;      ///< codec context
+    int extradata_parsed;       ///< we have attempted to parse extradata
+    int valid_extradata;        ///< extradata is valid, so we can calculate duration
+    int blocksize[2];           ///< short and long window sizes
+    int previous_blocksize;     ///< previous window size
+    int mode_blocksize[64];     ///< window size mapping for each mode
+    int mode_count;             ///< number of modes
+    int mode_mask;              ///< bitmask used to get the mode in each packet
+    int prev_mask;              ///< bitmask used to get the previous mode flag in each packet
+} VorbisParseContext;
+
+/**
+ * Initialize the Vorbis parser using headers in the extradata.
+ *
+ * @param avctx codec context
+ * @param s     Vorbis parser context
+ */
+int avpriv_vorbis_parse_extradata(AVCodecContext *avctx, VorbisParseContext *s);
+
+/**
+ * Get the duration for a Vorbis packet.
+ *
+ * avpriv_vorbis_parse_extradata() must have been successfully called prior to
+ * this in order for a correct duration to be returned.
+ *
+ * @param s        Vorbis parser context
+ * @param buf      buffer containing a Vorbis frame
+ * @param buf_size size of the buffer
+ */
+int avpriv_vorbis_parse_frame(VorbisParseContext *s, const uint8_t *buf,
+                              int buf_size);
+
+void avpriv_vorbis_parse_reset(VorbisParseContext *s);
+
+#endif /* AVCODEC_VORBIS_PARSER_H */