vobsub_read_packet() didn't check whether an array of AVPackets was
valid and therefore used uninitialized values.
Reviewed-by: Michael Niedermayer <michael@niedermayer.cc>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
When vobsub_read_packet() reads a packet, it uses a dedicated AVPacket
to get the subtitle timing and position from an FFDemuxSubtitlesQueue
(which has been filled with this data during reading the idx file in
vobsub_read_header); afterwards the actual subtitle data is read into
the packet destined for output and the timing and position are copied
to this packet. Afterwards, the local packet is unreferenced.
This can be simplified: Simply use the output packet to get the timing
and position from the FFDemuxSubtitlesQueue. The packet's size will be
zero afterwards, so that it can be directly used to read the actual
subtitle data. This makes copying the packet fields as well as
unreferencing the local packet unecessary and also removes an instance
of usage of sizeof(AVPacket) in libavformat.
The only difference is that the returned packet will already be flagged
as a keyframe. This currently only happens in compute_pkt_fields().
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
If an error happens in vobsub_read_header() after allocating the
AVFormatContext intended to read the sub-file, both the AVFormatContext
as well as the data in the subtitles queues leaks. This has been fixed.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
vobsub_read_header() uses an AVBPrint to write a string and up until
now, it collected the string stored in the AVBPrint via
av_bprint_finalize(), which might involve an allocation and copy of the
string. But this is unnecessary, as the lifetime of the returned string
does not exceed the lifetime of the AVBPrint. So use the string in the
AVBPrint directly.
This also makes it possible to easily fix a memleak: In certain error
situations, the string stored in the AVBPrint would not be freed (if it
was dynamically allocated). This has been fixed, too.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
When the VobSub demuxer was added, the fields it required were simply
added to the MpegDemuxContext (if the VobSub demuxer was selected at
all). The mpeg demuxer of course doesn't use these fields even if they
are there; and the VobSub demuxer doesn't use the old ones: It opens an
mpeg subdemuxer of its own and uses this where a mpeg demuxer is
required. Hence the two contexts can be split, saving memory.
Furthermore several headers can now be moved to the section that is
guarded by #if CONFIG_VOBSUB_DEMUXER (this even includes avassert.h
which was unguarded and has been added in 9cde9f70 despite not being
used in that patch).
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
In order to fix a potential memleak upon failure, 0b8956b2 made sure that
a buffer given by a pointer was freed upon error. But this pointer was
only initialized upon use and in several cases (Clang gives no fewer
than 13 -Wsometimes-uninitialized warnings) this meant that an
uninitialized pointer was used to free a buffer. So initialize the
pointer.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: James Almer <jamrial@gmail.com>
Extradata is supposed to be padded with AV_INPUT_BUFFER_PADDING_SIZE bytes,
yet the VobSub demuxer used av_strdup for the allocation of extradata.
This has been changed.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
It is supposed to be a flag. The only currently defined value is
AVIO_SEEKABLE_NORMAL, but other ones may be added in the future.
However all the current lavf code treats this field as a bool (mainly
for historical reasons).
Change all those cases to properly check for AVIO_SEEKABLE_NORMAL.
Currently, AVStream contains an embedded AVCodecContext instance, which
is used by demuxers to export stream parameters to the caller and by
muxers to receive stream parameters from the caller. It is also used
internally as the codec context that is passed to parsers.
In addition, it is also widely used by the callers as the decoding (when
demuxer) or encoding (when muxing) context, though this has been
officially discouraged since Libav 11.
There are multiple important problems with this approach:
- the fields in AVCodecContext are in general one of
* stream parameters
* codec options
* codec state
However, it's not clear which ones are which. It is consequently
unclear which fields are a demuxer allowed to set or a muxer allowed to
read. This leads to erratic behaviour depending on whether decoding or
encoding is being performed or not (and whether it uses the AVStream
embedded codec context).
- various synchronization issues arising from the fact that the same
context is used by several different APIs (muxers/demuxers,
parsers, bitstream filters and encoders/decoders) simultaneously, with
there being no clear rules for who can modify what and the different
processes being typically delayed with respect to each other.
- avformat_find_stream_info() making it necessary to support opening
and closing a single codec context multiple times, thus
complicating the semantics of freeing various allocated objects in the
codec context.
Those problems are resolved by replacing the AVStream embedded codec
context with a newly added AVCodecParameters instance, which stores only
the stream parameters exported by the demuxers or read by the muxers.
Some .idx files actually contain duplicate subtitle events:
timestamp: 00:07:52:600, filepos: 00004e800
timestamp: 00:07:52:600, filepos: 00004f800
The second will be dropped, because it has same pts, duration, and text
(the text is just a dummy empty string; the real data is retrieved when
actually reading vobsub subtitle packets).
Dropping this is probably not intended/safe, so avoid it.
See trac issue #4872 for a sample. This patch doesn't fix decoding of
the sample, though.
The stream ID is essentially an arbitrary number defined by the .idx
file headers. They have to match the IDs in the .sub stream. The vobsub
demuxer assumed the IDs would just start from 0, increassing by 1 for
each stream. This is not correct. In the sample I had, the IDs were
starting from 1, leading to no subtitles being displayed at all.
Fix this by using the correct stream ID.
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
