[FFmpeg-devel] [PATCH][RFC] nsv seeking

[Michael Niedermayer]

On Mon, Mar 16, 2009 at 12:15:27PM +0530, Jai Menon wrote:
> Hi,
> 
> Attached patch adds seeking support for NSV files. I'm not sure if its
> completely correct, hence the RFC ;). It works fine here and is an
> improvement compared to the current situation.
> Comments?
> 
> As a side note, the whole file could use a cleanup ;)

[...]
> @@ -347,12 +348,22 @@
>      PRINT(("NSV got infos; filepos %"PRId64"\n", url_ftell(pb)));
>  
>      if (table_entries_used > 0) {
> +        int i;
>          nsv->index_entries = table_entries_used;
>          if((unsigned)table_entries >= UINT_MAX / sizeof(uint32_t))
>              return -1;
> -        nsv->nsvf_index_data = av_malloc(table_entries * sizeof(uint32_t));
> -#warning "FIXME: Byteswap buffer as needed"
> -        get_buffer(pb, (unsigned char *)nsv->nsvf_index_data, table_entries * sizeof(uint32_t));
> +        nsv->nsvf_index_data = av_malloc(table_entries_used * sizeof(uint32_t));

integer overflow leading to heap buffer overflow


[...]
> @@ -453,6 +465,16 @@
>              av_set_pts_info(st, 64, framerate.den, framerate.num);
>              st->start_time = 0;
>              st->duration = av_rescale(nsv->duration, framerate.num, 1000*framerate.den);
> +
> +            for(i=0;i<nsv->index_entries;i++) {
> +                if(nsv->extended_index_data) {
> +                    av_add_index_entry(st, nsv->nsvf_index_data[i], nsv->extended_index_data[i],
> +                                       0, 0, AVINDEX_KEYFRAME);
> +                } else {
> +                    int64_t ts = av_rescale((i/nsv->index_entries)*nsv->duration, framerate.num, 1000*framerate.den);
> +                    av_add_index_entry(st, nsv->nsvf_index_data[i], ts, 0, 0, AVINDEX_KEYFRAME);
> +                }
> +            }
>          }
>          if (atag != T_NONE) {
>  #ifndef DISABLE_AUDIO

is there a reason for the temp table? i mean cant they be droped
in av_add_index_entry() directly?


> @@ -598,6 +620,11 @@
>          pkt->stream_index = st[NSV_ST_VIDEO]->index;//NSV_ST_VIDEO;
>          pkt->dts = nst->frame_offset;
>          pkt->flags |= nsv->state == NSV_HAS_READ_NSVS ? PKT_FLAG_KEY : 0; /* keyframe only likely on a sync frame */
> +
> +        if(!nsv->nsvf_index_data) {
> +            av_add_index_entry(st[NSV_ST_VIDEO], url_ftell(pb) - vsize, nst->frame_offset,
> +                               0, 0, nsv->state == NSV_HAS_READ_NSVS ? AVINDEX_KEYFRAME : 0);
> +        }
>  /*
>          for (i = 0; i < MIN(8, vsize); i++)
>              PRINT(("NSV video: [%d] = %02x\n", i, pkt->data[i]));

> @@ -683,15 +710,25 @@
>  
>  static int nsv_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
>  {
> -#if 0

ideally this should use the new seeking api


[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Frequently ignored awnser#1 FFmpeg bugs should be sent to our bugtracker. User
questions about the command line tools should be sent to the ffmpeg-user ML.
And questions about how to use libav* should be sent to the libav-user ML.
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