[FFmpeg-devel] [PATCH] mov: Support fake moov boxes disguised as hoov

Vittorio Giovara vittorio.giovara at gmail.com
Thu Aug 8 23:28:26 EEST 2019


Some broken apps generate files that have a fake box named 'hoov'
instead of a proper 'moov' one. This is speculation but it seems like
this box contains data to be modified later (eg as file grows in size,
data gets re-written) and its name is supposed to be changed to 'moov'
once it can be used as a 'moov', but for some reason this step is skipped.

Since this is not the first time this happens ('moov' boxes can be found
in 'free' ones) extend the existing hacks to search for the moov in such
boxes and skip the moov_retry since it needs to be found right away.
---
 libavformat/mov.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

This code is ugly, tips for improving it are welcome, or a full
rejection is ok too. Unfortunately I cannot share the sample, but VLC
is able to play it.
Vittorio

diff --git a/libavformat/mov.c b/libavformat/mov.c
index 24de5429d1..0c2986b72e 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -6800,10 +6800,10 @@ static int mov_read_default(MOVContext *c, AVIOContext *pb, MOVAtom atom)
         if (atom.size >= 8) {
             a.size = avio_rb32(pb);
             a.type = avio_rl32(pb);
-            if (a.type == MKTAG('f','r','e','e') &&
+            if (((a.type == MKTAG('f','r','e','e') && c->moov_retry) ||
+                  a.type == MKTAG('h','o','o','v')) &&
                 a.size >= 8 &&
-                c->fc->strict_std_compliance < FF_COMPLIANCE_STRICT &&
-                c->moov_retry) {
+                c->fc->strict_std_compliance < FF_COMPLIANCE_STRICT) {
                 uint8_t buf[8];
                 uint32_t *type = (uint32_t *)buf + 1;
                 if (avio_read(pb, buf, 8) != 8)
@@ -6811,7 +6811,7 @@ static int mov_read_default(MOVContext *c, AVIOContext *pb, MOVAtom atom)
                 avio_seek(pb, -8, SEEK_CUR);
                 if (*type == MKTAG('m','v','h','d') ||
                     *type == MKTAG('c','m','o','v')) {
-                    av_log(c->fc, AV_LOG_ERROR, "Detected moov in a free atom.\n");
+                    av_log(c->fc, AV_LOG_ERROR, "Detected moov in a free or hoov atom.\n");
                     a.type = MKTAG('m','o','o','v');
                 }
             }
-- 
2.22.0



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