From 72e33eec3a5e6d04d891e89ef0ab9d42054a6271 Mon Sep 17 00:00:00 2001
From: Paul B Mahol <onemda@gmail.com>
Date: Mon, 16 May 2016 22:39:03 +0200
Subject: [PATCH] avcodec/iff: add support for ANIMs with keyframes and
 concatenated ANIMs

Signed-off-by: Paul B Mahol <onemda@gmail.com>
---
 libavcodec/iff.c  | 15 ++++++---------
 libavformat/iff.c | 15 +++++++++++----
 2 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/libavcodec/iff.c b/libavcodec/iff.c
index 85fae1589e..9d7dce5596 100644
--- a/libavcodec/iff.c
+++ b/libavcodec/iff.c
@@ -63,7 +63,6 @@ typedef struct IffContext {
     uint8_t *video[2];
     unsigned video_size;
     uint32_t *pal[2];
-    int first;
 } IffContext;
 
 #define LUT8_PART(plane, v)                             \
@@ -422,7 +421,6 @@ static av_cold int decode_init(AVCodecContext *avctx)
         s->pal[1] = av_calloc(256, sizeof(*s->pal[1]));
         if (!s->video[0] || !s->video[1] || !s->pal[0] || !s->pal[1])
             return AVERROR(ENOMEM);
-        s->first = 1;
     }
 
     if ((err = extract_header(avctx, NULL)) < 0)
@@ -1322,17 +1320,11 @@ static int decode_frame(AVCodecContext *avctx,
     }
     s->init = 1;
 
-    if (s->compression <= 0xff && avctx->codec_tag == MKTAG('A', 'N', 'I', 'M')) {
+    if (s->compression <= 0xff && (avctx->codec_tag == MKTAG('A', 'N', 'I', 'M'))) {
         if (avctx->pix_fmt == AV_PIX_FMT_PAL8)
             memcpy(s->pal[0], s->frame->data[1], 256 * 4);
     }
 
-    if (s->compression > 0xff && s->first) {
-        memcpy(s->video[1], s->video[0], s->video_size);
-        memcpy(s->pal[1], s->pal[0], 256 * 4);
-        s->first = 0;
-    }
-
     switch (s->compression) {
     case 0x0:
         if (avctx->codec_tag == MKTAG('A', 'C', 'B', 'M')) {
@@ -1549,6 +1541,11 @@ static int decode_frame(AVCodecContext *avctx,
         return unsupported(avctx);
     }
 
+    if (s->compression <= 0xff && (avctx->codec_tag == MKTAG('A', 'N', 'I', 'M'))) {
+        memcpy(s->pal[1], s->pal[0], 256 * 4);
+        memcpy(s->video[1], s->video[0], s->video_size);
+    }
+
     if (s->compression > 0xff) {
         if (avctx->pix_fmt == AV_PIX_FMT_PAL8 || avctx->pix_fmt == AV_PIX_FMT_GRAY8) {
             buf = s->video[0];
diff --git a/libavformat/iff.c b/libavformat/iff.c
index f3db2820a5..275710b892 100644
--- a/libavformat/iff.c
+++ b/libavformat/iff.c
@@ -834,20 +834,27 @@ static int iff_read_packet(AVFormatContext *s,
     } else if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO &&
                st->codecpar->codec_tag  == ID_ANIM) {
         uint64_t data_size, orig_pos;
-        uint32_t chunk_id = 0;
+        uint32_t chunk_id, chunk_id2;
 
         while (!avio_feof(pb)) {
             if (avio_feof(pb))
                 return AVERROR_EOF;
 
+            orig_pos  = avio_tell(pb);
             chunk_id  = avio_rl32(pb);
             data_size = avio_rb32(pb);
-            orig_pos  = avio_tell(pb);
+            chunk_id2 = avio_rl32(pb);
 
-            if (chunk_id == ID_FORM)
+            if (chunk_id  == ID_FORM &&
+                chunk_id2 == ID_ILBM) {
+                avio_skip(pb, -4);
                 break;
-            else
+            } else if (chunk_id == ID_FORM &&
+                       chunk_id2 == ID_ANIM) {
+                continue;
+            } else {
                 avio_skip(pb, data_size);
+            }
         }
         ret = av_get_packet(pb, pkt, data_size);
         pkt->pos = orig_pos;