Changelog for 2.5.5 version

Entries are sorted chronologically from oldest to youngest within each release,
releases are sorted from youngest to oldest.

version 2.5.5:
- vp9: make above buffer pointer 32-byte aligned.
- avcodec/dnxhddec: Check that the frame is interlaced before using cur_field
- avformat/mov: Disallow ".." in dref unless use_absolute_path is set
- avformat/mov: Check for string truncation in mov_open_dref()
- avformat/mov: Use sizeof(filename) instead of a literal number
- eac3dec: fix scaling
- ac3_fixed: fix computation of spx_noise_blend
- ac3_fixed: fix out-of-bound read
- ac3dec_fixed: always use the USE_FIXED=1 variant of the AC3DecodeContext
- avcodec/012v: redesign main loop
- avcodec/012v: Check dimensions more completely
- asfenc: fix leaking asf->index_ptr on error
- avcodec/options_table: remove extradata_size from the AVOptions table
- ffmdec: limit the backward seek to the last resync position
- ffmdec: make sure the time base is valid
- ffmdec: fix infinite loop at EOF
- ffmdec: initialize f_cprv, f_stvi and f_stau
- avformat/rm: limit packet size
- avcodec/webp: validate the distance prefix code
- avcodec/rv10: check size of s->mb_width * s->mb_height
- eamad: check for out of bounds read
- mdec: check for out of bounds read
- arm: Suppress tags about used cpu arch and extensions
- aic: Fix decoding files with odd dimensions
- avcodec/tiff: move bpp check to after "end:"
- mxfdec: Fix the error handling for when strftime fails
- avcodec/opusdec: Fix delayed sample value
- avcodec/opusdec: Clear out pointers per packet
- avcodec/utils: Align YUV411 by as much as the other YUV variants
- vp9: fix segmentation map retention with threading enabled.
- webp: ensure that each transform is only used once
- doc/protocols/tcp: fix units of listen_timeout option value, from microseconds to milliseconds
- fix VP9 packet decoder returning 0 instead of the used data size
- avformat/flvenc: check that the codec_tag fits in the available bits
- avcodec/utils: use correct printf specifier in ff_set_sar
- avutil/imgutils: correctly check for negative SAR components
- swscale/utils: clear formatConvBuffer on allocation
- avformat/bit: only accept the g729 codec and 1 channel
- avformat/bit: check that pkt->size is 10 in write_packet
- avformat/adxdec: check avctx->channels for invalid values
- avformat/adxdec: set avctx->channels in adx_read_header
- Fix buffer_size argument to init_put_bits() in multiple encoders.
- mips/acelp_filters: fix incorrect register constraint
- avcodec/hevc_ps: Sanity checks for some log2_* values
- avcodec/zmbv: Check len before reading in decode_frame()
- avcodec/h264: Only reinit quant tables if a new PPS is allowed
- avcodec/snowdec: Fix ref value check
- swscale/utils: More carefully merge and clear coefficients outside the input
- avcodec/a64multienc: Assert that the Packet size does not grow
- avcodec/a64multienc: simplify frame handling code
- avcodec/a64multienc: fix use of uninitialized values in to_meta_with_crop
- avcodec/a64multienc: initialize mc_meta_charset to zero
- avcodec/a64multienc: don't set incorrect packet size
- avcodec/a64multienc: use av_frame_ref instead of copying the frame
- avcodec/x86/mlpdsp_init: Simplify mlp_filter_channel_x86()
- h264: initialize H264Context.avctx in init_thread_copy
- wtvdec: fix integer overflow resulting in errors with large files
- avcodec/gif: fix off by one in column offsetting finding

version 2.5.4:
- avcodec/arm/videodsp_armv5te: Fix linking failure with shared libs
- avcodec/mjpegdec: Skip blocks which are outside the visible area
- avcodec/h264_slice: ignore SAR changes in slices after the first
- avcodec/h264_slice: Check picture structure before setting the related fields
- avcodec/h264_slice: Do not change frame_num after the first slice
- avutil/opt: Fix type used to access AV_OPT_TYPE_SAMPLE_FMT
- avutil/opt: Fix types used to access AV_OPT_TYPE_PIXEL_FMT
- avcodec/h264: Be more strict on rejecting pps/sps changes
- avcodec/h264: Be more strict on rejecting pps_id changes
- avcodec/h264_ps: More completely check the bit depths
- avformat/thp: Check av_get_packet() for failure not only for partial output
- swscale/utils: Limit filter shifting so as not to read from prior the array
- avcodec/mpegvideo_motion: Fix gmc chroma dimensions
- avcodec/mjpegdec: Check number of components for JPEG-LS
- avcodec/mjpegdec: Check escape sequence validity
- avformat/mpc8: Use uint64_t in *_get_v() to avoid undefined behavior
- avformat/mpc8: fix broken pointer math
- avformat/mpc8: fix hang with fuzzed file
- avformat/tta: fix crash with corrupted files
- avcodec/ppc/idctdsp.c: POWER LE support in idct_add_altivec()
- swscale/input: fix rgba64 alpha non native
- swscale/input: Fix alpha of YA16 input
- libavcodec/ppc/mpegvideoencdsp.c: fix stack smashing in pix_norm1_altivec() and pix_sum_altivec()
- avformat/rmdec: Check for overflow in ff_rm_read_mdpr_codecdata()
- avformat/mpeg: do not count PES packets inside PES packets during probing
- hevc: always clip luma_log2_weight_denom
- rtpdec_h263_rfc2190: Clear the stored bits if discarding buffered data
- aacenc: correctly check returned value
- swscale: check memory allocations
- opt: check memory allocation
- avformat/utils: check for malloc failure
- avcodec/flac_parser: fix handling EOF if no headers are found
- avfilter/vf_framepack: Check and update frame_rate
- vp8: improve memory allocation checks
- configure: enable vsx together with altivec for ppc64el
- avcodec/hevc: Fix handling of skipped_bytes() reallocation failures
- qpeg: avoid pointless invalid memcpy()

version 2.5.3:
- vp9: fix parser return values in error case
- ffmpeg: Clear error message array at init.
- avcodec/dvdsubdec: fix accessing dangling pointers
- avcodec/dvdsubdec: error on bitmaps with size 0
- cmdutils: Use 64bit for file size/offset related variable in cmdutils_read_file()
- mov: Fix negative size calculation in mov_read_default().
- avformat/mov: fix integer overflow in mov_read_udta_string()
- mov: Fix overflow and error handling in read_tfra().
- mov: Avoid overflow with mov_metadata_raw()
- avcodec/dvdsubdec: fix out of bounds accesses
- avfilter/vf_sab: fix filtering tiny images
- avformat/flvdec: Increase string array size
- avformat/flvdec: do not inject dts=0 metadata packets which failed to be parsed into a new data stream
- avformat/cdxl: Fix integer overflow of image_size
- libavformat: Build hevc.o when building the RTP muxer

version 2.5.2:
- avcodec/indeo3: ensure offsets are non negative
- avcodec/h264: Check *log2_weight_denom
- avcodec/hevc_ps: Check diff_cu_qp_delta_depth
- avcodec/h264: Clear delayed_pic on deallocation
- avcodec/hevc: clear filter_slice_edges() on allocation
- avcodec/dcadec: Check that the added xch channel isnt already there
- avcodec/indeo3: use signed variables to avoid underflow
- swscale: increase yuv2rgb table headroom
- avformat/mov: fix integer overflow of size
- avformat/mov: check atom nesting depth
- avcodec/utvideodec: Fix handling of slice_height=0
- avcodec/xface: correct the XFACE_MAX_* values
- avcodec/vmdvideo: Check len before using it in method 3
- configure: create the tests directory like the doc directory
- mmvideo: check frame dimensions
- jvdec: check frame dimensions

version 2.5.1:
- lavu/frame: fix malloc error path in av_frame_copy_props()
- avformat/aviobuf: Check that avio_seek() target is non negative
- swresample/soxr_resample: fix error handling
- avformat/flvdec: fix potential use of uninitialized variables
- avformat/crypto: fix key vs iv typo
- configure: use use_pkg_config() instead of check_pkg_config() for libsmbclient
- avcodec/ppc/vp3dsp_altivec: POWER LE support to vp3_idct_add_altivec()
- avformat/matroskadec: fix handling of recursive SeekHead elements
- doc/examples/filtering_video: fix frame rate
- avcodec/mpegaudiodec_template: only allocate fdsp when its used
- doc/examples/transcoding: check encoder before using it
- update MAINTAINERS file
- POWER LE support in put_vp8_epel_h_altivec_core() put_vp8_epel_v_altivec_core() put_vp8_pixels16_altivec()
- POWER LE support in vc1_inv_trans_8x4_altivec()

version 2.5:
- HEVC/H.265 RTP payload format (draft v6) packetizer
- SUP/PGS subtitle demuxer
- ffprobe -show_pixel_formats option
- CAST128 symmetric block cipher, ECB mode
- STL subtitle demuxer and decoder
- libutvideo YUV 4:2:2 10bit support
- XCB-based screen-grabber
- UDP-Lite support (RFC 3828)
- xBR scaling filter
- AVFoundation screen capturing support
- ffserver supports codec private options
- creating DASH compatible fragmented MP4, MPEG-DASH segmenting muxer
- WebP muxer with animated WebP support
- zygoaudio decoding support
- APNG decoder and demuxer
- postproc visualization support

version 2.4:
- Icecast protocol
- ported lenscorrection filter from frei0r filter
- large optimizations in dctdnoiz to make it usable
- ICY metadata are now requested by default with the HTTP protocol
- support for using metadata in stream specifiers in fftools
- LZMA compression support in TIFF decoder
- support for H.261 RTP payload format (RFC 4587)
- HEVC/H.265 RTP payload format (draft v6) depacketizer
- added codecview filter to visualize information exported by some codecs
- Matroska 3D support thorugh side data
- HTML generation using texi2html is deprecated in favor of makeinfo/texi2any
- silenceremove filter

version 2.3:
- AC3 fixed-point decoding
- shuffleplanes filter
- subfile protocol
- Phantom Cine demuxer
- replaygain data export
- VP7 video decoder
- Alias PIX image encoder and decoder
- Improvements to the BRender PIX image decoder
- Improvements to the XBM decoder
- QTKit input device
- improvements to OpenEXR image decoder
- support decoding 16-bit RLE SGI images
- GDI screen grabbing for Windows
- alternative rendition support for HTTP Live Streaming
- AVFoundation input device
- Direct Stream Digital (DSD) decoder
- Magic Lantern Video (MLV) demuxer
- On2 AVC (Audio for Video) decoder
- support for decoding through DXVA2 in ffmpeg
- libbs2b-based stereo-to-binaural audio filter
- libx264 reference frames count limiting depending on level
- native Opus decoder
- display matrix export and rotation API
- WebVTT encoder
- showcqt multimedia filter
- zoompan filter
- signalstats filter
- hqx filter (hq2x, hq3x, hq4x)
- flanger filter
- Image format auto-detection
- LRC demuxer and muxer
- Samba protocol (via libsmbclient)
- WebM DASH Manifest muxer
- libfribidi support in drawtext

version 2.2:

- HNM version 4 demuxer and video decoder
- Live HDS muxer
- setsar/setdar filters now support variables in ratio expressions
- elbg filter
- string validation in ffprobe
- support for decoding through VDPAU in ffmpeg (the -hwaccel option)
- complete Voxware MetaSound decoder
- remove mp3_header_compress bitstream filter
- Windows resource files for shared libraries
- aeval filter
- stereoscopic 3d metadata handling
- WebP encoding via libwebp
- ATRAC3+ decoder
- VP8 in Ogg demuxing
- side & metadata support in NUT
- framepack filter
- XYZ12 rawvideo support in NUT
- Exif metadata support in WebP decoder
- OpenGL device
- Use metadata_header_padding to control padding in ID3 tags (currently used in
  MP3, AIFF, and OMA files), FLAC header, and the AVI "junk" block.
- Mirillis FIC video decoder
- Support DNx444
- libx265 encoder
- dejudder filter
- Autodetect VDA like all other hardware accelerations
- aliases and defaults for Ogg subtypes (opus, spx)

version 2.1:

- aecho filter
- perspective filter ported from libmpcodecs
- ffprobe -show_programs option
- compand filter
- RTMP seek support
- when transcoding with ffmpeg (i.e. not streamcopying), -ss is now accurate
  even when used as an input option. Previous behavior can be restored with
  the -noaccurate_seek option.
- ffmpeg -t option can now be used for inputs, to limit the duration of
  data read from an input file
- incomplete Voxware MetaSound decoder
- read EXIF metadata from JPEG
- DVB teletext decoder
- phase filter ported from libmpcodecs
- w3fdif filter
- Opus support in Matroska
- FFV1 version 1.3 is stable and no longer experimental
- FFV1: YUVA(444,422,420) 9, 10 and 16 bit support
- changed DTS stream id in lavf mpeg ps muxer from 0x8a to 0x88, to be
  more consistent with other muxers.
- adelay filter
- pullup filter ported from libmpcodecs
- ffprobe -read_intervals option
- Lossless and alpha support for WebP decoder
- Error Resilient AAC syntax (ER AAC LC) decoding
- Low Delay AAC (ER AAC LD) decoding
- mux chapters in ASF files
- SFTP protocol (via libssh)
- libx264: add ability to encode in YUVJ422P and YUVJ444P
- Fraps: use BT.709 colorspace by default for yuv, as reference fraps decoder does
- make decoding alpha optional for prores, ffv1 and vp6 by setting
  the skip_alpha flag.
- ladspa wrapper filter
- native VP9 decoder
- dpx parser
- max_error_rate parameter in ffmpeg
- PulseAudio output device
- ReplayGain scanner
- Enhanced Low Delay AAC (ER AAC ELD) decoding (no LD SBR support)
- Linux framebuffer output device
- HEVC decoder
- raw HEVC, HEVC in MOV/MP4, HEVC in Matroska, HEVC in MPEG-TS demuxing
- mergeplanes filter

version 2.0:

- curves filter
- reference-counting for AVFrame and AVPacket data
- ffmpeg now fails when input options are used for output file
  or vice versa
- support for Monkey's Audio versions from 3.93
- perms and aperms filters
- audio filtering support in ffplay
- 10% faster aac encoding on x86 and MIPS
- sine audio filter source
- WebP demuxing and decoding support
- ffmpeg options -filter_script and -filter_complex_script, which allow a
  filtergraph description to be read from a file
- OpenCL support
- audio phaser filter
- separatefields filter
- libquvi demuxer
- uniform options syntax across all filters
- telecine filter
- interlace filter
- smptehdbars source
- inverse telecine filters (fieldmatch and decimate)
- colorbalance filter
- colorchannelmixer filter
- The matroska demuxer can now output proper verbatim ASS packets. It will
  become the default at the next libavformat major bump.
- decent native animated GIF encoding
- asetrate filter
- interleave filter
- timeline editing with filters
- vidstabdetect and vidstabtransform filters for video stabilization using
  the vid.stab library
- astats filter
- trim and atrim filters
- ffmpeg -t and -ss (output-only) options are now sample-accurate when
  transcoding audio
- Matroska muxer can now put the index at the beginning of the file.
- extractplanes filter
- avectorscope filter
- ADPCM DTK decoder
- ADP demuxer
- RSD demuxer
- RedSpark demuxer
- ADPCM IMA Radical decoder
- zmq filters
- DCT denoiser filter (dctdnoiz)
- Wavelet denoiser filter ported from libmpcodecs as owdenoise (formerly "ow")
- Apple Intermediate Codec decoder
- Escape 130 video decoder
- FTP protocol support
- V4L2 output device
- 3D LUT filter (lut3d)
- SMPTE 302M audio encoder
- support for slice multithreading in libavfilter
- Hald CLUT support (generation and filtering)
- VC-1 interlaced B-frame support
- support for WavPack muxing (raw and in Matroska)
- XVideo output device
- vignette filter
- True Audio (TTA) encoder
- Go2Webinar decoder
- mcdeint filter ported from libmpcodecs
- sab filter ported from libmpcodecs
- ffprobe -show_chapters option
- WavPack encoding through libwavpack
- rotate filter
- spp filter ported from libmpcodecs
- libgme support
- psnr filter

version 1.2:

- VDPAU hardware acceleration through normal hwaccel
- SRTP support
- Error diffusion dither in Swscale
- Chained Ogg support
- Theora Midstream reconfiguration support
- EVRC decoder
- audio fade filter
- filtering audio with unknown channel layout
- allpass, bass, bandpass, bandreject, biquad, equalizer, highpass, lowpass
  and treble audio filter
- improved showspectrum filter, with multichannel support and sox-like colors
- histogram filter
- tee muxer
- il filter ported from libmpcodecs
- support ID3v2 tags in ASF files
- encrypted TTA stream decoding support
- RF64 support in WAV muxer
- noise filter ported from libmpcodecs
- Subtitles character encoding conversion
- blend filter
- stereo3d filter ported from libmpcodecs

version 1.1:

- stream disposition information printing in ffprobe
- filter for loudness analysis following EBU R128
- Opus encoder using libopus
- ffprobe -select_streams option
- Pinnacle TARGA CineWave YUV16 decoder
- TAK demuxer, decoder and parser
- DTS-HD demuxer
- remove -same_quant, it hasn't worked for years
- FFM2 support
- X-Face image encoder and decoder
- 24-bit FLAC encoding
- multi-channel ALAC encoding up to 7.1
- metadata (INFO tag) support in WAV muxer
- subtitles raw text decoder
- support for building DLLs using MSVC
- LVF demuxer
- ffescape tool
- metadata (info chunk) support in CAF muxer
- field filter ported from libmpcodecs
- AVR demuxer
- geq filter ported from libmpcodecs
- remove ffserver daemon mode
- AST muxer/demuxer
- new expansion syntax for drawtext
- BRender PIX image decoder
- ffprobe -show_entries option
- ffprobe -sections option
- ADPCM IMA Dialogic decoder
- BRSTM demuxer
- animated GIF decoder and demuxer
- PVF demuxer
- subtitles filter
- IRCAM muxer/demuxer
- Paris Audio File demuxer
- Virtual concatenation demuxer
- VobSub demuxer
- JSON captions for TED talks decoding support
- SOX Resampler support in libswresample
- aselect filter
- SGI RLE 8-bit / Silicon Graphics RLE 8-bit video decoder
- Silicon Graphics Motion Video Compressor 1 & 2 decoder
- Silicon Graphics Movie demuxer
- apad filter
- Resolution & pixel format change support with multithreading for H.264
- documentation split into per-component manuals
- pp (postproc) filter ported from MPlayer
- NIST Sphere demuxer
- MPL2, VPlayer, MPlayer, AQTitle, PJS and SubViewer v1 subtitles demuxers and decoders
- Sony Wave64 muxer
- adobe and limelight publisher authentication in RTMP
- data: URI scheme
- support building on the Plan 9 operating system
- kerndeint filter ported from MPlayer
- histeq filter ported from VirtualDub
- Megalux Frame demuxer
- 012v decoder
- Improved AVC Intra decoding support

version 1.0:

- INI and flat output in ffprobe
- Scene detection in libavfilter
- Indeo Audio decoder
- channelsplit audio filter
- setnsamples audio filter
- atempo filter
- ffprobe -show_data option
- RTMPT protocol support
- iLBC encoding/decoding via libilbc
- Microsoft Screen 1 decoder
- join audio filter
- audio channel mapping filter
- Microsoft ATC Screen decoder
- RTSP listen mode
- TechSmith Screen Codec 2 decoder
- AAC encoding via libfdk-aac
- Microsoft Expression Encoder Screen decoder
- RTMPS protocol support
- RTMPTS protocol support
- RTMPE protocol support
- RTMPTE protocol support
- showwaves and showspectrum filter
- LucasArts SMUSH SANM playback support
- LucasArts SMUSH VIMA audio decoder (ADPCM)
- LucasArts SMUSH demuxer
- SAMI, RealText and SubViewer demuxers and decoders
- Heart Of Darkness PAF playback support
- iec61883 device
- asettb filter
- new option: -progress
- 3GPP Timed Text encoder/decoder
- GeoTIFF decoder support
- ffmpeg -(no)stdin option
- Opus decoder using libopus
- caca output device using libcaca
- alphaextract and alphamerge filters
- concat filter
- flite filter
- Canopus Lossless Codec decoder
- bitmap subtitles in filters (experimental and temporary)
- MP2 encoding via TwoLAME
- bmp parser
- smptebars source
- asetpts filter
- hue filter
- ICO muxer
- SubRip encoder and decoder without embedded timing
- edge detection filter
- framestep filter
- ffmpeg -shortest option is now per-output file
  -pass and -passlogfile are now per-output stream
- volume measurement filter
- Ut Video encoder
- Microsoft Screen 2 decoder
- smartblur filter ported from MPlayer
- CPiA decoder
- decimate filter ported from MPlayer
- RTP depacketization of JPEG
- Smooth Streaming live segmenter muxer
- F4V muxer
- sendcmd and asendcmd filters
- WebVTT demuxer and decoder (simple tags supported)
- RTP packetization of JPEG
- faststart option in the MOV/MP4 muxer
- support for building with MSVC

version 0.11:

- Fixes: CVE-2012-2772, CVE-2012-2774, CVE-2012-2775, CVE-2012-2776, CVE-2012-2777,
         CVE-2012-2779, CVE-2012-2782, CVE-2012-2783, CVE-2012-2784, CVE-2012-2785,
         CVE-2012-2786, CVE-2012-2787, CVE-2012-2788, CVE-2012-2789, CVE-2012-2790,
         CVE-2012-2791, CVE-2012-2792, CVE-2012-2793, CVE-2012-2794, CVE-2012-2795,
         CVE-2012-2796, CVE-2012-2797, CVE-2012-2798, CVE-2012-2799, CVE-2012-2800,
         CVE-2012-2801, CVE-2012-2802, CVE-2012-2803, CVE-2012-2804,
- v408 Quicktime and Microsoft AYUV Uncompressed 4:4:4:4 encoder and decoder
- setfield filter
- CDXL demuxer and decoder
- Apple ProRes encoder
- ffprobe -count_packets and -count_frames options
- Sun Rasterfile Encoder
- ID3v2 attached pictures reading and writing
- WMA Lossless decoder
- bluray protocol
- blackdetect filter
- libutvideo encoder wrapper (--enable-libutvideo)
- swapuv filter
- bbox filter
- XBM encoder and decoder
- RealAudio Lossless decoder
- ZeroCodec decoder
- tile video filter
- Metal Gear Solid: The Twin Snakes demuxer
- OpenEXR image decoder
- removelogo filter
- drop support for ffmpeg without libavfilter
- drawtext video filter: fontconfig support
- ffmpeg -benchmark_all option
- super2xsai filter ported from libmpcodecs
- add libavresample audio conversion library for compatibility
- MicroDVD decoder
- Avid Meridien (AVUI) encoder and decoder
- accept + prefix to -pix_fmt option to disable automatic conversions.
- complete audio filtering in libavfilter and ffmpeg
- add fps filter
- vorbis parser
- png parser
- audio mix filter
- ffv1: support (draft) version 1.3

version 0.10:

- Fixes: CVE-2011-3929, CVE-2011-3934, CVE-2011-3935, CVE-2011-3936,
         CVE-2011-3937, CVE-2011-3940, CVE-2011-3941, CVE-2011-3944,
         CVE-2011-3945, CVE-2011-3946, CVE-2011-3947, CVE-2011-3949,
         CVE-2011-3950, CVE-2011-3951, CVE-2011-3952
- v410 Quicktime Uncompressed 4:4:4 10-bit encoder and decoder
- SBaGen (SBG) binaural beats script demuxer
- OpenMG Audio muxer
- Timecode extraction in DV and MOV
- thumbnail video filter
- XML output in ffprobe
- asplit audio filter
- tinterlace video filter
- astreamsync audio filter
- amerge audio filter
- ISMV (Smooth Streaming) muxer
- GSM audio parser
- SMJPEG muxer
- XWD encoder and decoder
- Automatic thread count based on detection number of (available) CPU cores
- y41p Brooktree Uncompressed 4:1:1 12-bit encoder and decoder
- ffprobe -show_error option
- Avid 1:1 10-bit RGB Packer codec
- v308 Quicktime Uncompressed 4:4:4 encoder and decoder
- yuv4 libquicktime packed 4:2:0 encoder and decoder
- ffprobe -show_frames option
- silencedetect audio filter
- ffprobe -show_program_version, -show_library_versions, -show_versions options
- rv34: frame-level multi-threading
- optimized iMDCT transform on x86 using SSE for for mpegaudiodec
- Improved PGS subtitle decoder
- dumpgraph option to lavfi device
- r210 and r10k encoders
- ffwavesynth decoder
- aviocat tool
- ffeval tool
- support encoding and decoding 4-channel SGI images

version 0.9:

- openal input device added
- boxblur filter added
- BWF muxer
- Flash Screen Video 2 decoder
- lavfi input device added
- added avconv, which is almost the same for now, except
for a few incompatible changes in the options, which will hopefully make them
easier to use. The changes are:
    * The options placement is now strictly enforced! While in theory the
      options for ffmpeg should be given in [input options] -i INPUT [output
      options] OUTPUT order, in practice it was possible to give output options
      before the -i and it mostly worked. Except when it didn't - the behavior was
      a bit inconsistent. In avconv, it is not possible to mix input and output
      options. All non-global options are reset after an input or output filename.
    * All per-file options are now truly per-file - they apply only to the next
      input or output file and specifying different values for different files
      will now work properly (notably -ss and -t options).
    * All per-stream options are now truly per-stream - it is possible to
      specify which stream(s) should a given option apply to. See the Stream
      specifiers section in the avconv manual for details.
    * In ffmpeg some options (like -newvideo/-newaudio/...) are irregular in the
      sense that they're specified after the output filename instead of before,
      like all other options. In avconv this irregularity is removed, all options
      apply to the next input or output file.
    * -newvideo/-newaudio/-newsubtitle options were removed. Not only were they
      irregular and highly confusing, they were also redundant. In avconv the -map
      option will create new streams in the output file and map input streams to
      them. E.g. avconv -i INPUT -map 0 OUTPUT will create an output stream for
      each stream in the first input file.
    * The -map option now has slightly different and mor