[FFmpeg-devel] [PR] WIP: avformat/demux: in case of no timestamps, calculate dts based on previous dts and duration (PR #21380)

[FFmpeg-devel] [PR] WIP: avformat/demux: in case of no timestamps, calculate dts based on previous dts and duration (PR #21380)

[Jan Ekström via ffmpeg-devel]

PR #21380 opened by Jan Ekström (jeeb)
URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21380
Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21380.patch

Adds DTS to packets which would otherwise break tbr calculation
within libavformat, as well as packet rate calculation in ffmpeg.

An example of such input would be an MPEG-TS stream where a whole
GOP is put into a single PES packet.

Co-authored-by: Jan Ekström <jan.ekstrom@24i.com>

Signed-off-by: Jan Ekström <jan.ekstrom@24i.com>


From 1d5affdfdef4c361cbd79d65abc16a9a4ab5fd89 Mon Sep 17 00:00:00 2001
From: Martin Machalek <martin.machalek@24i.com>
Date: Fri, 28 Apr 2023 15:09:22 +0200
Subject: [PATCH] avformat/demux: in case of no timestamps, calculate dts based
 on previous dts and duration
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Adds DTS to packets which would otherwise break tbr calculation
within libavformat, as well as packet rate calculation in ffmpeg.

An example of such input would be an MPEG-TS stream where a whole
GOP is put into a single PES packet.

Co-authored-by: Jan Ekström <jan.ekstrom@24i.com>

Signed-off-by: Jan Ekström <jan.ekstrom@24i.com>
---
 libavformat/demux.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/libavformat/demux.c b/libavformat/demux.c
index b40739dc3a..67b54aba3b 100644
--- a/libavformat/demux.c
+++ b/libavformat/demux.c
@@ -1152,6 +1152,12 @@ static void compute_pkt_fields(AVFormatContext *s, AVStream *st,
     if (!onein_oneout)
         // This should happen on the first packet
         update_initial_timestamps(s, pkt->stream_index, pkt->dts, pkt->pts, pkt);
+
+    if (pkt->dts == AV_NOPTS_VALUE && pkt->pts == AV_NOPTS_VALUE &&
+        !is_relative(sti->cur_dts) && sti->cur_dts != AV_NOPTS_VALUE &&
+        pkt->duration > 0)
+        pkt->dts = sti->cur_dts + pkt->duration;
+
     if (pkt->dts > sti->cur_dts)
         sti->cur_dts = pkt->dts;
 
-- 
2.49.1

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