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

[Vittorio Giovara]

On Thu, Aug 8, 2019 at 10:28 PM Vittorio Giovara <vittorio.giovara at gmail.com>
wrote:

> 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');
>                  }
>              }
> --
>

ping?
-- 
Vittorio