[FFmpeg-devel] [PATCH 4/6] Un-mark IMA APC as intra-only

["Tomas Härdin" <git@haerdin.se>]

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From dd84044af61931988e43bd58c202fe4e7ca7069a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tomas=20H=C3=A4rdin?= <git@haerdin.se>
Date: Tue, 26 Dec 2023 16:30:35 +0100
Subject: [PATCH 4/6] Un-mark IMA APC as intra-only

Packets must be decoded in order.
There is no way to seek and get a bitexact decode.
---
 libavcodec/codec_desc.c | 2 +-
 libavformat/apc.c       | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/libavcodec/codec_desc.c b/libavcodec/codec_desc.c
index 432a9c9ea6..899c082c83 100644
--- a/libavcodec/codec_desc.c
+++ b/libavcodec/codec_desc.c
@@ -2431,7 +2431,7 @@ static const AVCodecDescriptor codec_descriptors[] = {
         .type      = AVMEDIA_TYPE_AUDIO,
         .name      = "adpcm_ima_apc",
         .long_name = NULL_IF_CONFIG_SMALL("ADPCM IMA CRYO APC"),
-        .props     = AV_CODEC_PROP_INTRA_ONLY | AV_CODEC_PROP_LOSSY,
+        .props     = AV_CODEC_PROP_LOSSY,
     },
     {
         .id        = AV_CODEC_ID_ADPCM_VIMA,
diff --git a/libavformat/apc.c b/libavformat/apc.c
index 7765c53088..d1891954a8 100644
--- a/libavformat/apc.c
+++ b/libavformat/apc.c
@@ -75,8 +75,13 @@ static int apc_read_header(AVFormatContext *s)
 
 static int apc_read_packet(AVFormatContext *s, AVPacket *pkt)
 {
+    int first = avio_tell(s->pb) == 32;
     if (av_get_packet(s->pb, pkt, MAX_READ_SIZE) <= 0)
         return AVERROR(EIO);
+    // each IMA APC packet depends on the one before for bitexact decode
+    // extradata is used to initialize the decoder
+    if (first)
+        pkt->flags |= AV_PKT_FLAG_KEY;
     pkt->stream_index = 0;
     return 0;
 }
-- 
2.39.2


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