This patch adds a new static function get_qt_priv_data() that takes care
of the initial retrieval of the fourcc and codec ID for A_QUICKTIME and
V_QUICKTIME. It also normalizes noncompliant private data found in some
older files that incorrectly starts with the fourcc by
expanding/shifting the data by 4 bytes, and storing the data size at the
start. This is important in order to make the private data work as
expected and without false positives with the rest of the code in the
A_QUICKTIME and V_QUICKTIME blocks (and most likely in other places as
well).
Mats
>From 3dcdf6bb857587715868751eff61a484b3d65fdc Mon Sep 17 00:00:00 2001
From: Mats Peterson <matsp...@yahoo.com>
Date: Fri, 8 Jan 2016 16:07:14 +0100
Subject: [PATCH] lavf/matroskadec: Normalize noncompliant
A_QUICKTIME/V_QUICKTIME private data
This patch adds a new static function get_qt_priv_data() that takes care
of the initial retrieval of the fourcc and codec ID for A_QUICKTIME and
V_QUICKTIME. It also normalizes noncompliant private data found in some
older files that incorrectly starts with the fourcc by expanding/shifting
the data by 4 bytes, and storing the data size at the start. This is
important in order to make the private data work as expected and without
false positives with the rest of the code in the A_QUICKTIME and
V_QUICKTIME blocks (and most likely in other places as well).
Mats
---
libavformat/matroskadec.c | 49 +++++++++++++++++++++++++++++++++------------
1 file changed, 36 insertions(+), 13 deletions(-)
diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
index be4e300..4f95566 100644
--- a/libavformat/matroskadec.c
+++ b/libavformat/matroskadec.c
@@ -1708,6 +1708,34 @@ static void mkv_stereo_mode_display_mul(int stereo_mode, int *h_width, int *h_he
}
}
+static int get_qt_priv_data(MatroskaTrack *track, uint32_t *fourcc, enum AVCodecID *codec_id)
+{
+ const AVCodecTag *codec_tags;
+
+ codec_tags = track->type == MATROSKA_TRACK_TYPE_VIDEO ?
+ ff_codec_movvideo_tags : ff_codec_movaudio_tags;
+
+ *fourcc = AV_RL32(track->codec_priv.data + 4);
+ *codec_id = ff_codec_get_id(codec_tags, *fourcc);
+
+ /* Normalize noncompliant private data that starts with the fourcc
+ * by expanding/shifting the data by 4 bytes and storing the data
+ * size at the start. */
+ if (ff_codec_get_id(codec_tags, AV_RL32(track->codec_priv.data))) {
+ if (!(track->codec_priv.data = av_realloc(track->codec_priv.data,
+ track->codec_priv.size + 4)))
+ return AVERROR(ENOMEM);
+ memmove(track->codec_priv.data + 4, track->codec_priv.data,
+ track->codec_priv.size);
+ track->codec_priv.size += 4;
+ AV_WB32(track->codec_priv.data, track->codec_priv.size);
+ *fourcc = AV_RL32(track->codec_priv.data + 4);
+ *codec_id = ff_codec_get_id(ff_codec_movvideo_tags, *fourcc);
+ }
+
+ return 0;
+}
+
static int matroska_parse_tracks(AVFormatContext *s)
{
MatroskaDemuxContext *matroska = s->priv_data;
@@ -1861,14 +1889,12 @@ static int matroska_parse_tracks(AVFormatContext *s)
fourcc = st->codec->codec_tag;
extradata_offset = FFMIN(track->codec_priv.size, 18);
} else if (!strcmp(track->codec_id, "A_QUICKTIME")
- && (track->codec_priv.size >= 36)
+ /* Normally 36, but allow noncompliant private data */
+ && (track->codec_priv.size >= 32)
&& (track->codec_priv.data)) {
- fourcc = AV_RL32(track->codec_priv.data + 4);
- codec_id = ff_codec_get_id(ff_codec_movaudio_tags, fourcc);
- if (ff_codec_get_id(ff_codec_movaudio_tags, AV_RL32(track->codec_priv.data))) {
- fourcc = AV_RL32(track->codec_priv.data);
- codec_id = ff_codec_get_id(ff_codec_movaudio_tags, fourcc);
- }
+ int ret = get_qt_priv_data(track, &fourcc, &codec_id);
+ if (ret < 0)
+ return ret;
if (fourcc == 0) {
if (track->audio.bitdepth == 8) {
fourcc = MKTAG('r','a','w',' ');
@@ -1881,12 +1907,9 @@ static int matroska_parse_tracks(AVFormatContext *s)
} else if (!strcmp(track->codec_id, "V_QUICKTIME") &&
(track->codec_priv.size >= 21) &&
(track->codec_priv.data)) {
- fourcc = AV_RL32(track->codec_priv.data + 4);
- codec_id = ff_codec_get_id(ff_codec_movvideo_tags, fourcc);
- if (ff_codec_get_id(ff_codec_movvideo_tags, AV_RL32(track->codec_priv.data))) {
- fourcc = AV_RL32(track->codec_priv.data);
- codec_id = ff_codec_get_id(ff_codec_movvideo_tags, fourcc);
- }
+ int ret = get_qt_priv_data(track, &fourcc, &codec_id);
+ if (ret < 0)
+ return ret;
if (codec_id == AV_CODEC_ID_NONE && AV_RL32(track->codec_priv.data+4) == AV_RL32("SMI ")) {
fourcc = MKTAG('S','V','Q','3');
codec_id = ff_codec_get_id(ff_codec_movvideo_tags, fourcc);
--
1.7.10.4
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