It only uses an AVIOContext and an AVBPrint.
When doing so, it turned out that several non-users of
ff_read_line_to_bprint_overwrite() and ff_bprint_to_codecpar_extradata()
relied on libavformat/internal.h to include bprint.h or avstring.h
for them. In order to avoid a repeat of this and in order to reduce
unnecessary dependencies, a forward declaration of struct AVBPrint is
used instead of including bprint.h.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
This is possible now that the next-API is gone.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
Signed-off-by: James Almer <jamrial@gmail.com>
When there are potentially annotation (i.e. metadata) fields to write,
au_get_annotations() is called to produce a string with them. To do so,
it uses an AVBPrint which is finalized to create the string. This is
wasteful, because it always leads to an allocation even if the string
actually fits into the internal buffer of the AVBPrint. This commit
changes this by making au_get_annotations() modify an AVBPrint that
resides on the stack of the caller (i.e. of au_write_header()).
Furthermore, the AVBPrint is now checked for truncation; limiting
the allocations implicit in the AVBPrint allowed to offload the overflow
checks. Notice that these were not correct before: The size parameter of
avio_write() is an int, yet the string in the AVBPrint was allowed to
grow bigger than INT_MAX. And if the length of the string was so near
UINT_MAX that the length + 32 overflowed, the old code would write the
first eight bytes of the string and nothing more, leading to an invalid
file.
Finally, the special case in which the metadata dictionary of the
AVFormatContext is empty (in which case one still has to write eight
binary zeroes) is now no longer treated specially, because this case
no longer incurs any allocation.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
This av_freep(&key) in conjunction with the fact that the loop condition
checks for key != NULL was equivalent to a av_freep(&key) + a break
immediately thereafter. But given that there is an av_freep(&key)
directly after the loop, the av_freep(&key) is unnecessary and the break
can also be added explicitly.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
To make it consistent with other muxers.
The user can still control the generic flushing behaviour after write_header
(same way as after packets) using the -flush_packets option, the default
typically means to flush unless a non-streamed file output is used.
Therefore this change should have no adverse effect on streaming, even if it is
assumed that the first packet has a clean buffer, so small seekbacks within the
output buffer work even when the IO context is not seekable.
Signed-off-by: Marton Balint <cus@passwd.hu>
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.
Also check number of streams and give error message why muxing failed.
This prevents muxing unsupported codec with known and supported tag.
Signed-off-by: Paul B Mahol <onemda@gmail.com>
Andreas Rheinhardt
Andreas Rheinhardt
Michael Niedermayer
Limin Wang
Marton Balint
Carl Eugen Hoyos
Paul B Mahol
Anton Khirnov
Thomas Bernard
Michael Niedermayer
Carl Eugen Hoyos
Diego Biurrun
Justin Ruggles