Posting this again.
A lot of files have CRC included.
The CRC only covers 34 bytes at most from the frame but it should still be
enough for some amount of error detection.
Patch attached.
>From 2d7f310482e204d28c1408144b432b3f8e8dc866 Mon Sep 17 00:00:00 2001
From: Lynne <d...@lynne.ee>
Date: Wed, 6 Mar 2019 17:04:04 +0000
Subject: [PATCH 2/3] mpegaudiodec_template: add ability to check CRC
A lot of files have CRC included.
The CRC only covers 34 bytes at most from the frame but it should still be
enough for some amount of error detection.
---
libavcodec/mpegaudiodec_template.c | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)
diff --git a/libavcodec/mpegaudiodec_template.c b/libavcodec/mpegaudiodec_template.c
index 3f1674e827..3d7e3ba4f2 100644
--- a/libavcodec/mpegaudiodec_template.c
+++ b/libavcodec/mpegaudiodec_template.c
@@ -27,6 +27,7 @@
#include "libavutil/attributes.h"
#include "libavutil/avassert.h"
#include "libavutil/channel_layout.h"
+#include "libavutil/crc.h"
#include "libavutil/float_dsp.h"
#include "libavutil/libm.h"
#include "avcodec.h"
@@ -1565,9 +1566,22 @@ static int mp_decode_frame(MPADecodeContext *s, OUT_INT **samples,
init_get_bits(&s->gb, buf + HEADER_SIZE, (buf_size - HEADER_SIZE) * 8);
- /* skip error protection field */
- if (s->error_protection)
- skip_bits(&s->gb, 16);
+ if (s->error_protection) {
+ uint16_t crc = get_bits(&s->gb, 16);
+ if (s->err_recognition & AV_EF_CRCCHECK) {
+ const int sec_len = s->lsf ? ((s->nb_channels == 1) ? 9 : 17) :
+ ((s->nb_channels == 1) ? 17 : 32);
+ const AVCRC *crc_tab = av_crc_get_table(AV_CRC_16_ANSI);
+ uint32_t crc_cal = av_crc(crc_tab, UINT16_MAX, &buf[2], 2);
+ crc_cal = av_crc(crc_tab, crc_cal, &buf[6], sec_len);
+
+ if (av_bswap16(crc) ^ crc_cal) {
+ av_log(s->avctx, AV_LOG_ERROR, "CRC mismatch!\n");
+ if (s->err_recognition & AV_EF_EXPLODE)
+ return AVERROR_INVALIDDATA;
+ }
+ }
+ }
switch(s->layer) {
case 1:
--
2.27.0.rc0
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