From 3f3531f5607cd973488260aa00c752c3a74496a5 Mon Sep 17 00:00:00 2001
From: wm4 <wm4@nowhere>
Date: Thu, 30 May 2013 17:40:55 +0200
Subject: demux_mkv: fix wavpack in mkv

Libav introduced a silent API breakage by changing what wavpack packets
the libavcodec decoder accepts. Originally the libavcodec codec accepted
Matroska-style wavpack packets. Libav commit 9b6f47c removed this
capability from the libavcodec code, and added code to libavformat's
Matroska demuxer to "rearrange" wavpack packets. Since demux_mkv still
sent Matroska-style packets, playback failed.

Fix this by "rearranging" packets in demux_mkv as well by copying
libavformat's code. (The best kind of fix.)

Tested with [CCCP]_Mega_Lossless_Audio_Test.mkv, as well as with a
sample generated by mkvmerge.
---
 demux/demux_mkv.c | 92 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)

(limited to 'demux/demux_mkv.c')

diff --git a/demux/demux_mkv.c b/demux/demux_mkv.c
index 3d8efaf211..4b0decff1a 100644
--- a/demux/demux_mkv.c
+++ b/demux/demux_mkv.c
@@ -2058,6 +2058,97 @@ static void handle_realaudio(demuxer_t *demuxer, mkv_track_t *track,
     }
 }
 
+// Copied from libavformat/matroskadec.c (FFmpeg 310f9dd / 2013-05-30)
+// Originally added with Libav commit 9b6f47c
+// License: LGPL v2.1 or later
+// Author header: The FFmpeg Project (this function still came from Libav)
+// Modified to use talloc, removed ffmpeg/libav specific error codes.
+static int libav_parse_wavpack(mkv_track_t *track, uint8_t *src,
+                               uint8_t **pdst, int *size)
+{
+    uint8_t *dst = NULL;
+    int dstlen   = 0;
+    int srclen   = *size;
+    uint32_t samples;
+    uint16_t ver;
+    int offset = 0;
+
+    if (srclen < 12 || track->private_size < 2)
+        return -1;
+
+    ver = AV_RL16(track->private_data);
+
+    samples = AV_RL32(src);
+    src    += 4;
+    srclen -= 4;
+
+    while (srclen >= 8) {
+        int multiblock;
+        uint32_t blocksize;
+        uint8_t *tmp;
+
+        uint32_t flags = AV_RL32(src);
+        uint32_t crc   = AV_RL32(src + 4);
+        src    += 8;
+        srclen -= 8;
+
+        multiblock = (flags & 0x1800) != 0x1800;
+        if (multiblock) {
+            if (srclen < 4)
+                goto fail;
+            blocksize = AV_RL32(src);
+            src    += 4;
+            srclen -= 4;
+        } else
+            blocksize = srclen;
+
+        if (blocksize > srclen)
+            goto fail;
+
+        tmp = talloc_realloc(NULL, dst, uint8_t, dstlen + blocksize + 32);
+        if (!tmp)
+            goto fail;
+        dst     = tmp;
+        dstlen += blocksize + 32;
+
+        AV_WL32(dst + offset,      MKTAG('w', 'v', 'p', 'k')); // tag
+        AV_WL32(dst + offset + 4,  blocksize + 24);         // blocksize - 8
+        AV_WL16(dst + offset + 8,  ver);                    // version
+        AV_WL16(dst + offset + 10, 0);                      // track/index_no
+        AV_WL32(dst + offset + 12, 0);                      // total samples
+        AV_WL32(dst + offset + 16, 0);                      // block index
+        AV_WL32(dst + offset + 20, samples);                // number of samples
+        AV_WL32(dst + offset + 24, flags);                  // flags
+        AV_WL32(dst + offset + 28, crc);                    // crc
+        memcpy (dst + offset + 32, src, blocksize);         // block data
+
+        src    += blocksize;
+        srclen -= blocksize;
+        offset += blocksize + 32;
+    }
+
+    *pdst = dst;
+    *size = dstlen;
+
+    return 0;
+
+fail:
+    talloc_free(dst);
+    return -1;
+}
+
+static void mkv_parse_packet(mkv_track_t *track, bstr *buffer)
+{
+    if (track->a_formattag == mmioFOURCC('W', 'V', 'P', 'K')) {
+        int size = buffer->len;
+        uint8_t *parsed;
+        if (libav_parse_wavpack(track, buffer->start, &parsed, &size) >= 0) {
+            buffer->start = parsed;
+            buffer->len = size;
+        }
+    }
+}
+
 struct block_info {
     uint64_t duration;
     bool simple, keyframe;
@@ -2204,6 +2295,7 @@ static int handle_block(demuxer_t *demuxer, struct block_info *block_info)
                 handle_realaudio(demuxer, track, block, keyframe);
             else {
                 bstr buffer = demux_mkv_decode(track, block, 1);
+                mkv_parse_packet(track, &buffer);
                 if (buffer.start) {
                     demux_packet_t *dp =
                         new_demux_packet_from(buffer.start, buffer.len);
-- 
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