From: wangyaqiang via ffmpeg-devel <ffmpeg-devel@ffmpeg.org>
To: ffmpeg-devel@ffmpeg.org
Cc: wangyaqiang <1035567130@qq.com>
Subject: [FFmpeg-devel] [PATCH] libavformat/matroskadec: fix the pos value error in the packet
Date: Thu, 26 Feb 2026 21:48:44 +0800
Message-ID: <tencent_ADAA483C463FF918F5BB6AF2510EE1252B0A@qq.com> (raw)
When parsing a block, the passed data corresponds to the pos value.
However, when constructing a packet, some offsets are made to the data,
so the pos in the packet does not correspond to the position in the file.
Signed-off-by: wangyaqiang <1035567130@qq.com>
---
libavformat/matroskadec.c | 4 ++--
tests/ref/seek/lavf-mkv | 44 +++++++++++++++++-----------------
tests/ref/seek/mkv-codec-delay | 44 +++++++++++++++++-----------------
3 files changed, 46 insertions(+), 46 deletions(-)
diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
index 503b99b286..0215855019 100644
--- a/libavformat/matroskadec.c
+++ b/libavformat/matroskadec.c
@@ -4116,7 +4116,7 @@ static int matroska_parse_block(MatroskaDemuxContext *matroska, AVBufferRef *buf
int n, flags, laces = 0;
uint64_t num;
int trust_default_duration;
-
+ uint8_t *data_start = data;
av_assert1(buf);
ffio_init_read_context(&pb, data, size);
@@ -4200,7 +4200,7 @@ static int matroska_parse_block(MatroskaDemuxContext *matroska, AVBufferRef *buf
if (cluster_time != (uint64_t)-1 && (block_time >= 0 || cluster_time >= -block_time))
track->end_timecode =
FFMAX(track->end_timecode, timecode + block_duration);
-
+ pos += (data - data_start);
for (n = 0; n < laces; n++) {
int64_t lace_duration = block_duration*(n+1) / laces - block_duration*n / laces;
uint8_t *out_data = data;
diff --git a/tests/ref/seek/lavf-mkv b/tests/ref/seek/lavf-mkv
index e327959058..40af3381ca 100644
--- a/tests/ref/seek/lavf-mkv
+++ b/tests/ref/seek/lavf-mkv
@@ -1,48 +1,48 @@
-ret: 0 st: 1 flags:1 dts:-0.011000 pts:-0.011000 pos: 689 size: 208
+ret: 0 st: 1 flags:1 dts:-0.011000 pts:-0.011000 pos: 693 size: 208
ret: 0 st:-1 flags:0 ts:-1.000000
-ret: 0 st: 0 flags:1 dts: 0.000000 pts: 0.000000 pos: 905 size: 27837
+ret: 0 st: 0 flags:1 dts: 0.000000 pts: 0.000000 pos: 909 size: 27837
ret: 0 st:-1 flags:1 ts: 1.894167
-ret: 0 st: 0 flags:1 dts: 0.960000 pts: 0.960000 pos: 292321 size: 27834
+ret: 0 st: 0 flags:1 dts: 0.960000 pts: 0.960000 pos: 292325 size: 27834
ret: 0 st: 0 flags:0 ts: 0.788000
-ret: 0 st: 0 flags:1 dts: 0.960000 pts: 0.960000 pos: 292321 size: 27834
+ret: 0 st: 0 flags:1 dts: 0.960000 pts: 0.960000 pos: 292325 size: 27834
ret: 0 st: 0 flags:1 ts:-0.317000
-ret: 0 st: 0 flags:1 dts: 0.000000 pts: 0.000000 pos: 905 size: 27837
+ret: 0 st: 0 flags:1 dts: 0.000000 pts: 0.000000 pos: 909 size: 27837
ret:-1 st: 1 flags:0 ts: 2.577000
ret: 0 st: 1 flags:1 ts: 1.471000
-ret: 0 st: 1 flags:1 dts: 0.982000 pts: 0.982000 pos: 320165 size: 209
+ret: 0 st: 1 flags:1 dts: 0.982000 pts: 0.982000 pos: 320169 size: 209
ret: 0 st:-1 flags:0 ts: 0.365002
-ret: 0 st: 0 flags:1 dts: 0.480000 pts: 0.480000 pos: 146873 size: 27925
+ret: 0 st: 0 flags:1 dts: 0.480000 pts: 0.480000 pos: 146877 size: 27925
ret: 0 st:-1 flags:1 ts:-0.740831
-ret: 0 st: 0 flags:1 dts: 0.000000 pts: 0.000000 pos: 905 size: 27837
+ret: 0 st: 0 flags:1 dts: 0.000000 pts: 0.000000 pos: 909 size: 27837
ret:-1 st: 0 flags:0 ts: 2.153000
ret: 0 st: 0 flags:1 ts: 1.048000
-ret: 0 st: 0 flags:1 dts: 0.960000 pts: 0.960000 pos: 292321 size: 27834
+ret: 0 st: 0 flags:1 dts: 0.960000 pts: 0.960000 pos: 292325 size: 27834
ret: 0 st: 1 flags:0 ts:-0.058000
-ret: 0 st: 1 flags:1 dts:-0.011000 pts:-0.011000 pos: 689 size: 208
+ret: 0 st: 1 flags:1 dts:-0.011000 pts:-0.011000 pos: 693 size: 208
ret: 0 st: 1 flags:1 ts: 2.836000
-ret: 0 st: 1 flags:1 dts: 0.982000 pts: 0.982000 pos: 320165 size: 209
+ret: 0 st: 1 flags:1 dts: 0.982000 pts: 0.982000 pos: 320169 size: 209
ret:-1 st:-1 flags:0 ts: 1.730004
ret: 0 st:-1 flags:1 ts: 0.624171
-ret: 0 st: 0 flags:1 dts: 0.480000 pts: 0.480000 pos: 146873 size: 27925
+ret: 0 st: 0 flags:1 dts: 0.480000 pts: 0.480000 pos: 146877 size: 27925
ret: 0 st: 0 flags:0 ts:-0.482000
-ret: 0 st: 0 flags:1 dts: 0.000000 pts: 0.000000 pos: 905 size: 27837
+ret: 0 st: 0 flags:1 dts: 0.000000 pts: 0.000000 pos: 909 size: 27837
ret: 0 st: 0 flags:1 ts: 2.413000
-ret: 0 st: 0 flags:1 dts: 0.960000 pts: 0.960000 pos: 292321 size: 27834
+ret: 0 st: 0 flags:1 dts: 0.960000 pts: 0.960000 pos: 292325 size: 27834
ret:-1 st: 1 flags:0 ts: 1.307000
ret: 0 st: 1 flags:1 ts: 0.201000
-ret: 0 st: 1 flags:1 dts:-0.011000 pts:-0.011000 pos: 689 size: 208
+ret: 0 st: 1 flags:1 dts:-0.011000 pts:-0.011000 pos: 693 size: 208
ret: 0 st:-1 flags:0 ts:-0.904994
-ret: 0 st: 0 flags:1 dts: 0.000000 pts: 0.000000 pos: 905 size: 27837
+ret: 0 st: 0 flags:1 dts: 0.000000 pts: 0.000000 pos: 909 size: 27837
ret: 0 st:-1 flags:1 ts: 1.989173
-ret: 0 st: 0 flags:1 dts: 0.960000 pts: 0.960000 pos: 292321 size: 27834
+ret: 0 st: 0 flags:1 dts: 0.960000 pts: 0.960000 pos: 292325 size: 27834
ret: 0 st: 0 flags:0 ts: 0.883000
-ret: 0 st: 0 flags:1 dts: 0.960000 pts: 0.960000 pos: 292321 size: 27834
+ret: 0 st: 0 flags:1 dts: 0.960000 pts: 0.960000 pos: 292325 size: 27834
ret: 0 st: 0 flags:1 ts:-0.222000
-ret: 0 st: 0 flags:1 dts: 0.000000 pts: 0.000000 pos: 905 size: 27837
+ret: 0 st: 0 flags:1 dts: 0.000000 pts: 0.000000 pos: 909 size: 27837
ret:-1 st: 1 flags:0 ts: 2.672000
ret: 0 st: 1 flags:1 ts: 1.566000
-ret: 0 st: 1 flags:1 dts: 0.982000 pts: 0.982000 pos: 320165 size: 209
+ret: 0 st: 1 flags:1 dts: 0.982000 pts: 0.982000 pos: 320169 size: 209
ret: 0 st:-1 flags:0 ts: 0.460008
-ret: 0 st: 0 flags:1 dts: 0.480000 pts: 0.480000 pos: 146873 size: 27925
+ret: 0 st: 0 flags:1 dts: 0.480000 pts: 0.480000 pos: 146877 size: 27925
ret: 0 st:-1 flags:1 ts:-0.645825
-ret: 0 st: 0 flags:1 dts: 0.000000 pts: 0.000000 pos: 905 size: 27837
+ret: 0 st: 0 flags:1 dts: 0.000000 pts: 0.000000 pos: 909 size: 27837
diff --git a/tests/ref/seek/mkv-codec-delay b/tests/ref/seek/mkv-codec-delay
index 04561eb876..3a6667cf61 100644
--- a/tests/ref/seek/mkv-codec-delay
+++ b/tests/ref/seek/mkv-codec-delay
@@ -1,48 +1,48 @@
-ret: 0 st: 0 flags:1 dts:-0.007000 pts:-0.007000 pos: 748 size: 320
+ret: 0 st: 0 flags:1 dts:-0.007000 pts:-0.007000 pos: 752 size: 320
ret: 0 st:-1 flags:0 ts:-1.000000
-ret: 0 st: 0 flags:1 dts:-0.007000 pts:-0.007000 pos: 748 size: 320
+ret: 0 st: 0 flags:1 dts:-0.007000 pts:-0.007000 pos: 752 size: 320
ret: 0 st:-1 flags:1 ts: 1.894167
-ret: 0 st: 0 flags:1 dts: 1.014000 pts: 1.014000 pos: 9306 size: 268
+ret: 0 st: 0 flags:1 dts: 1.014000 pts: 1.014000 pos: 9310 size: 268
ret: 0 st: 0 flags:0 ts: 0.788000
-ret: 0 st: 0 flags:1 dts: 0.794000 pts: 0.794000 pos: 7358 size: 154
+ret: 0 st: 0 flags:1 dts: 0.794000 pts: 0.794000 pos: 7362 size: 154
ret: 0 st: 0 flags:1 ts:-0.317000
-ret: 0 st: 0 flags:1 dts:-0.007000 pts:-0.007000 pos: 748 size: 320
+ret: 0 st: 0 flags:1 dts:-0.007000 pts:-0.007000 pos: 752 size: 320
ret:-1 st:-1 flags:0 ts: 2.576668
ret: 0 st:-1 flags:1 ts: 1.470835
-ret: 0 st: 0 flags:1 dts: 1.014000 pts: 1.014000 pos: 9306 size: 268
+ret: 0 st: 0 flags:1 dts: 1.014000 pts: 1.014000 pos: 9310 size: 268
ret: 0 st: 0 flags:0 ts: 0.365000
-ret: 0 st: 0 flags:1 dts: 0.374000 pts: 0.374000 pos: 3963 size: 150
+ret: 0 st: 0 flags:1 dts: 0.374000 pts: 0.374000 pos: 3967 size: 150
ret: 0 st: 0 flags:1 ts:-0.741000
-ret: 0 st: 0 flags:1 dts:-0.007000 pts:-0.007000 pos: 748 size: 320
+ret: 0 st: 0 flags:1 dts:-0.007000 pts:-0.007000 pos: 752 size: 320
ret:-1 st:-1 flags:0 ts: 2.153336
ret: 0 st:-1 flags:1 ts: 1.047503
-ret: 0 st: 0 flags:1 dts: 1.014000 pts: 1.014000 pos: 9306 size: 268
+ret: 0 st: 0 flags:1 dts: 1.014000 pts: 1.014000 pos: 9310 size: 268
ret: 0 st: 0 flags:0 ts:-0.058000
-ret: 0 st: 0 flags:1 dts:-0.007000 pts:-0.007000 pos: 748 size: 320
+ret: 0 st: 0 flags:1 dts:-0.007000 pts:-0.007000 pos: 752 size: 320
ret: 0 st: 0 flags:1 ts: 2.836000
-ret: 0 st: 0 flags:1 dts: 1.014000 pts: 1.014000 pos: 9306 size: 268
+ret: 0 st: 0 flags:1 dts: 1.014000 pts: 1.014000 pos: 9310 size: 268
ret:-1 st:-1 flags:0 ts: 1.730004
ret: 0 st:-1 flags:1 ts: 0.624171
-ret: 0 st: 0 flags:1 dts: 0.614000 pts: 0.614000 pos: 5903 size: 159
+ret: 0 st: 0 flags:1 dts: 0.614000 pts: 0.614000 pos: 5907 size: 159
ret: 0 st: 0 flags:0 ts:-0.482000
-ret: 0 st: 0 flags:1 dts:-0.007000 pts:-0.007000 pos: 748 size: 320
+ret: 0 st: 0 flags:1 dts:-0.007000 pts:-0.007000 pos: 752 size: 320
ret: 0 st: 0 flags:1 ts: 2.413000
-ret: 0 st: 0 flags:1 dts: 1.014000 pts: 1.014000 pos: 9306 size: 268
+ret: 0 st: 0 flags:1 dts: 1.014000 pts: 1.014000 pos: 9310 size: 268
ret:-1 st:-1 flags:0 ts: 1.306672
ret: 0 st:-1 flags:1 ts: 0.200839
-ret: 0 st: 0 flags:1 dts: 0.194000 pts: 0.194000 pos: 2512 size: 159
+ret: 0 st: 0 flags:1 dts: 0.194000 pts: 0.194000 pos: 2516 size: 159
ret: 0 st: 0 flags:0 ts:-0.905000
-ret: 0 st: 0 flags:1 dts:-0.007000 pts:-0.007000 pos: 748 size: 320
+ret: 0 st: 0 flags:1 dts:-0.007000 pts:-0.007000 pos: 752 size: 320
ret: 0 st: 0 flags:1 ts: 1.989000
-ret: 0 st: 0 flags:1 dts: 1.014000 pts: 1.014000 pos: 9306 size: 268
+ret: 0 st: 0 flags:1 dts: 1.014000 pts: 1.014000 pos: 9310 size: 268
ret: 0 st:-1 flags:0 ts: 0.883340
-ret: 0 st: 0 flags:1 dts: 0.894000 pts: 0.894000 pos: 8154 size: 155
+ret: 0 st: 0 flags:1 dts: 0.894000 pts: 0.894000 pos: 8158 size: 155
ret: 0 st:-1 flags:1 ts:-0.222493
-ret: 0 st: 0 flags:1 dts:-0.007000 pts:-0.007000 pos: 748 size: 320
+ret: 0 st: 0 flags:1 dts:-0.007000 pts:-0.007000 pos: 752 size: 320
ret:-1 st: 0 flags:0 ts: 2.672000
ret: 0 st: 0 flags:1 ts: 1.566000
-ret: 0 st: 0 flags:1 dts: 1.014000 pts: 1.014000 pos: 9306 size: 268
+ret: 0 st: 0 flags:1 dts: 1.014000 pts: 1.014000 pos: 9310 size: 268
ret: 0 st:-1 flags:0 ts: 0.460008
-ret: 0 st: 0 flags:1 dts: 0.474000 pts: 0.474000 pos: 4768 size: 153
+ret: 0 st: 0 flags:1 dts: 0.474000 pts: 0.474000 pos: 4772 size: 153
ret: 0 st:-1 flags:1 ts:-0.645825
-ret: 0 st: 0 flags:1 dts:-0.007000 pts:-0.007000 pos: 748 size: 320
+ret: 0 st: 0 flags:1 dts:-0.007000 pts:-0.007000 pos: 752 size: 320
--
2.50.1 (Apple Git-155)
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next reply other threads:[~2026-02-26 13:49 UTC|newest]
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2026-02-26 13:48 wangyaqiang via ffmpeg-devel [this message]
-- strict thread matches above, loose matches on Subject: below --
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2026-02-26 12:58 wangyaqiang via ffmpeg-devel
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