[FFmpeg-devel] [PATCH] mlp_parser: fetch a new timestamp when major sync is found

[Jan Ekström]

From: Hendrik Leppkes <h.leppkes at gmail.com>

Decoding can only start on a major sync and the parser discards
any data received until that point. Therefore, previously received
timestamps are no longer relevant to the data being returned from
the parser.

Additionally, adds a test which remuxes an existing TrueHD sample
with the first keyframe dropped using copyinkf, and then demuxes
this remux with ffprobe. Previously this would have pushed the
first random access point packet out as pts=1, even though it would
have contained the data received from packet containing pts=13.

With this fix, the first data received from the parser properly
contains the pts of the packet in which it was contained.

Fixes #9428

Co-authored-by: Jan Ekström <jeebjp at gmail.com>
---
 libavcodec/mlp_parser.c                 |  1 +
 tests/fate/truehd.mak                   | 12 ++++++++++++
 tests/ref/fate/truehd-parser-timestamps | 26 +++++++++++++++++++++++++
 3 files changed, 39 insertions(+)
 create mode 100644 tests/ref/fate/truehd-parser-timestamps

diff --git a/libavcodec/mlp_parser.c b/libavcodec/mlp_parser.c
index 9fea7db955..70d7b3f601 100644
--- a/libavcodec/mlp_parser.c
+++ b/libavcodec/mlp_parser.c
@@ -96,6 +96,7 @@ static int mlp_parse(AVCodecParserContext *s,
                 return ret;
             }
 
+            s->fetch_timestamp = 1;
             return i - 7;
         }
 
diff --git a/tests/fate/truehd.mak b/tests/fate/truehd.mak
index 7da8c93cff..6f451cc327 100644
--- a/tests/fate/truehd.mak
+++ b/tests/fate/truehd.mak
@@ -13,5 +13,17 @@ fate-truehd-core-bsf: CMD = md5pipe -i $(TARGET_SAMPLES)/truehd/atmos.thd -c:a c
 fate-truehd-core-bsf: CMP = oneline
 fate-truehd-core-bsf: REF = 3aa5d0c7825051f3657b71fd6135183b
 
+# Tests that the result from reading a copyinkf remux with the first random
+# access point dropped will receive the correct timestamp for the first packet,
+# which is not the packet of the first packet read.
+FATE_TRUEHD-$(call ALLYES, FILE_PROTOCOL PIPE_PROTOCOL TRUEHD_DEMUXER \
+                           MLP_PARSER MATROSKA_MUXER NOISE_BSF) \
+                           += fate-truehd-parser-timestamps
+fate-truehd-parser-timestamps: CMD = stream_remux "truehd" \
+    "$(TARGET_SAMPLES)/lossless-audio/truehd_5.1.raw" "matroska" \
+    "-map 0:a -copyinkf -bsf:a noise=drop=not\(n\)*key -t 0.030" \
+    "-c copy -copyts"
+fate-truehd-parser-timestamps: CMP = diff
+
 FATE_SAMPLES_AUDIO += $(FATE_TRUEHD-yes)
 fate-truehd: $(FATE_TRUEHD-yes)
diff --git a/tests/ref/fate/truehd-parser-timestamps b/tests/ref/fate/truehd-parser-timestamps
new file mode 100644
index 0000000000..94d5a05640
--- /dev/null
+++ b/tests/ref/fate/truehd-parser-timestamps
@@ -0,0 +1,26 @@
+#tb 0: 1/1000
+#media_type 0: audio
+#codec_id 0: truehd
+#sample_rate 0: 48000
+#channel_layout 0: 60f
+#channel_layout_name 0: 5.1(side)
+0,         13,         13,        1,      368, 0x256aaaad
+0,         14,         14,        1,      190, 0x7b975b90, F=0x0
+0,         15,         15,        1,      178, 0xfdc85dc0, F=0x0
+0,         16,         16,        1,      184, 0x3a605a1c, F=0x0
+0,         17,         17,        1,      184, 0xf00e5aef, F=0x0
+0,         18,         18,        1,      186, 0x95125c74, F=0x0
+0,         18,         18,        1,      184, 0xc6ae624e, F=0x0
+0,         19,         19,        1,      186, 0x5f9e5de9, F=0x0
+0,         20,         20,        1,      188, 0x80135cc7, F=0x0
+0,         21,         21,        1,      188, 0x10dc5a3d, F=0x0
+0,         22,         22,        1,      188, 0x63ff5980, F=0x0
+0,         23,         23,        1,      198, 0x42265ec5, F=0x0
+0,         23,         23,        1,      210, 0x4d2f6d78, F=0x0
+0,         24,         24,        1,      202, 0x44b6654f, F=0x0
+0,         25,         25,        1,      192, 0x098e6271, F=0x0
+0,         26,         26,        1,      194, 0x090f691d, F=0x0
+0,         27,         27,        1,      382, 0x88b0ac79
+0,         28,         28,        1,      196, 0xf0765d20, F=0x0
+0,         28,         28,        1,      188, 0x72c65e8d, F=0x0
+0,         29,         29,        1,      186, 0x913a5fcb, F=0x0
-- 
2.35.1