Go to file
Andreas Rheinhardt 163bb9ac0a avformat/aviobuf: Avoid allocating buffer when using dynamic buffer
Up until now, using a dynamic buffer entailed at least three
allocations: One for the AVIOContext, one for the AVIOContext's opaque
(which, among other things, contains the small write buffer), and one
for the big buffer that is independently allocated that is returned when
calling avio_close_dyn_buf().

It is possible to avoid the third allocation if one doesn't use a
packetized dynamic buffer, if all the data written so far fit into the
write buffer and if one does not require the actual (big) buffer to have
an indefinite lifetime. This is done by making avio_get_dyn_buf() return
a pointer to the data in the write buffer if nothing has been written to
the main buffer yet. The dynamic buffer will then be freed using
ffio_free_dynamic_buffer (which needed to be modified not to call
avio_close_dyn_buf() internally).

So a typical use-case like:

size = avio_close_dyn_buf(dyn_pb, &buf);
do something with buf
av_free(buf);

can be converted to:

size = avio_get_dyn_buf(dyn_pb, &buf);
do something with buf
ffio_free_dynamic_buffer(&dyn_pb);

In more complex scenarios this can simplify freeing as well, because it
is now clear that freeing always has to be performed via
ffio_free_dynamic_buffer().

Of course, in case this saves an allocation it also saves a memcpy.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
2019-11-28 15:20:36 -03:00
compat compat/cuda: Change inclusion guards 2019-08-05 12:07:09 +02:00
doc doc/encoder: add the missing qsv encoders 2019-11-28 23:30:31 +08:00
ffbuild build: add support for building CUDA files with clang 2019-08-04 19:08:08 +02:00
fftools fftools/ffmpeg_opt: Fix mixed declarations and code 2019-11-06 20:38:03 +01:00
libavcodec avcodec/vp8: fix multiple ff_thread_finish_setup() calls 2019-11-28 18:44:01 +01:00
libavdevice avdevice/decklink: add option to drop frames till timecode is seen 2019-11-18 10:01:03 +05:30
libavfilter avfilter/vf_libvmaf: Check for av_frame_alloc failure 2019-11-28 18:44:01 +01:00
libavformat avformat/aviobuf: Avoid allocating buffer when using dynamic buffer 2019-11-28 15:20:36 -03:00
libavresample avresample: remove deprecated attribute from the AVAudioResampleContext struct 2018-01-09 10:56:53 -03:00
libavutil avutil/hwcontext_cuda: allow using primary CUDA device context 2019-11-26 16:24:40 +01:00
libpostproc Bump minor versions again on master to keep 4.2 versions separate from master 2019-07-21 18:36:31 +02:00
libswresample swresample/audioconvert: fix invalid left shift for 64bit sample format 2019-09-26 16:22:47 +02:00
libswscale swscale/swscale_unscaled: fix gbrap10be md5 different on big endian system 2019-11-01 14:43:16 +01:00
presets
tests fate/cbs: add initial AV1 tests 2019-11-19 14:49:03 -03:00
tools tools/target_dec_fuzzer: Adjust threshold for VP9 2019-11-24 22:56:32 +01:00
.gitattributes fate: add SCC test 2017-01-27 17:06:42 +01:00
.gitignore tools/python: add script to convert TensorFlow model (.pb) to native model (.model) 2019-07-01 10:23:47 -03:00
.travis.yml Merge commit '899ee03088d55152a48830df0899887f055da1de' 2019-03-14 15:53:16 -03:00
Changelog avcodec: add mvha video decoder 2019-11-27 23:54:20 +01:00
configure avcodec: add mvha video decoder 2019-11-27 23:54:20 +01:00
CONTRIBUTING.md
COPYING.GPLv2
COPYING.GPLv3
COPYING.LGPLv2.1
COPYING.LGPLv3
CREDITS
INSTALL.md INSTALL.md: Fix Markdown formatting 2019-01-31 10:29:16 -09:00
LICENSE.md LICENSE: Add missing libraries that need --enable-version3. 2019-08-12 02:25:39 +02:00
MAINTAINERS MAINTAINERS: add myself to OMX 2019-08-23 17:07:05 -07:00
Makefile tools: Add fuzzer for demuxers 2019-05-31 22:44:30 +02:00
README.md Remove the ffserver program 2018-01-06 18:31:37 +00:00
RELEASE RELEASE: Update value for post 4.2 branch 2019-07-21 18:37:32 +02:00

FFmpeg README

FFmpeg is a collection of libraries and tools to process multimedia content such as audio, video, subtitles and related metadata.

Libraries

  • libavcodec provides implementation of a wider range of codecs.
  • libavformat implements streaming protocols, container formats and basic I/O access.
  • libavutil includes hashers, decompressors and miscellaneous utility functions.
  • libavfilter provides a mean to alter decoded Audio and Video through chain of filters.
  • libavdevice provides an abstraction to access capture and playback devices.
  • libswresample implements audio mixing and resampling routines.
  • libswscale implements color conversion and scaling routines.

Tools

  • ffmpeg is a command line toolbox to manipulate, convert and stream multimedia content.
  • ffplay is a minimalistic multimedia player.
  • ffprobe is a simple analysis tool to inspect multimedia content.
  • Additional small tools such as aviocat, ismindex and qt-faststart.

Documentation

The offline documentation is available in the doc/ directory.

The online documentation is available in the main website and in the wiki.

Examples

Coding examples are available in the doc/examples directory.

License

FFmpeg codebase is mainly LGPL-licensed with optional components licensed under GPL. Please refer to the LICENSE file for detailed information.

Contributing

Patches should be submitted to the ffmpeg-devel mailing list using git format-patch or git send-email. Github pull requests should be avoided because they are not part of our review process and will be ignored.