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  1. 04 Aug, 2019 1 commit
    • Stefan Schoenefeld's avatar
      avcodec/h263dec: fix hwaccel decoding · 39a5c0ac
      Stefan Schoenefeld authored 
      Recently we encountered an issue when decoding a h.263 file:

FFmpeg will freeze when decoding h.263 video with NVDEC. Turns out this is not directly related to NVDEC but is a problem that shows with several other HW decoders like VDPAU, though the exact kind of error is different (either error messages or freezing[1]). The root cause is that ff_thread_finish_setup() is called twice per frame from ff_h263_decode_frame(). This is not supported by ff_thread_finish_setup() and specifically checked for and warned against in the functions code. The issue is also specific to hw accelerated decoding only as the second call to ff_thread_finish_setup() is only issued when hw acceleration is on. The fix is simple: add a check that the first call is only send when hw acceleration is off, and the second call only when hw acceleration is on (see attached patch). This works fine as far as I was able to test with vdpau and nvdec/nvcuvid hw decoding. The patch also adds NVDEC to the hw config list if available.

I also noticed a secondary issue when browsing through the code which is that, according to documentation, ff_thread_finish_setup() should only be called if the codec implements update_thread_context(), which h263dec does not. The patch does not address this and I'm not sure any action needs to be taken here at all.

[1] This is depending on whether or not the hw decoder sets the  HWACCEL_CAPS_ASYNC_SAFE flag
Signed-off-by: 's avatarTimo Rothenpieler <timo@rothenpieler.org>
      39a5c0ac
  3. 03 Aug, 2019 15 commits
  5. 02 Aug, 2019 4 commits
  7. 01 Aug, 2019 2 commits
  9. 31 Jul, 2019 8 commits
  11. 30 Jul, 2019 4 commits
  13. 29 Jul, 2019 6 commits
    • Andreas Rheinhardt's avatar
      cbs_mpeg2: Fix parsing the last unit · fd93d5ef
      Andreas Rheinhardt authored 
      There is one way to find out if avpriv_find_start_code has found a start
code or not: One has to check whether the state variable contains a
start code, i.e. whether the three most significant bytes are 0x00 00 01.
Checking for whether the return value is the end of the designated
buffer is not enough: If the last four bytes constitute a start code,
the return value is also the end of the buffer. This happens with
sequence_end_codes which have been ignored for exactly this reason,
although e.g. all three files used for fate tests of cbs_mpeg2 contain
sequence_end_codes.
Signed-off-by: 's avatarAndreas Rheinhardt <andreas.rheinhardt@gmail.com>
      fd93d5ef
    • Andreas Rheinhardt's avatar
      cbs_mpeg2: Rearrange start code search · 276b21a5
      Andreas Rheinhardt authored 
      1. Currently, cbs_mpeg2_split_fragment uses essentially three variables
to hold the start code values found by avpriv_find_start_code. By
rearranging the code, one of them can be omitted.
2. The return value of avpriv_find_start_code points to the byte after
the byte containing the start code identifier (or to the byte after the
last byte of the fragment's data if no start code was found), but
cbs_mpeg2_split_fragment needs to work with the pointer to the byte
containing the start code identifier; it already did this, but in a
clumsy way. This has been changed.
3. Also use the correct type for the variable holding the
CodedBitstreamUnitType.
Signed-off-by: 's avatarAndreas Rheinhardt <andreas.rheinhardt@gmail.com>
      276b21a5
    • Andreas Rheinhardt's avatar
      cbs_mpeg2: Decompose Sequence End · 0e66e1b6
      Andreas Rheinhardt authored 
      Sequence End units (or actually, sequence_end_codes) have up until now
not been decomposed; in fact due to a bug in cbs_mpeg2_split_fragment they
have mostly been treated as part of the preceding unit. So implement
decomposing them as preparation for fixing said bug.
Signed-off-by: 's avatarAndreas Rheinhardt <andreas.rheinhardt@gmail.com>
      0e66e1b6
    • Andreas Rheinhardt's avatar
      cbs_h264: Improve adding SEI messages · ae49993c
      Andreas Rheinhardt authored 
      Up until now, if an SEI messages was to be added to a fragment, it was
tried to add said SEI message to the first SEI NAL unit of the fragment
and if this SEI NAL unit already contained H264_NAL_SEI SEI messages (an
arbitrary limit imposed by cbs_h264), adding failed; if there was no SEI
NAL unit, a new one has been added.
With this commit, the fragment is searched for further NAL units to add
the SEI messages to. If all of them are full, a new SEI NAL unit is added.
Signed-off-by: 's avatarAndreas Rheinhardt <andreas.rheinhardt@gmail.com>
      ae49993c
    • Andreas Rheinhardt's avatar
      cbs: Don't set AVBuffer's opaque · 4e7e30bb
      Andreas Rheinhardt authored 
      cbs is currently inconsistent regarding the opaque field that can be
used as a special argument to av_buffer_create in order to be used
during freeing the buffer: ff_cbs_alloc_unit_content and all the free
functions used name this parameter as if it should contain a pointer to
the unit whose content is about to be created; but both
ff_cbs_alloc_unit_content as well as ff_cbs_h264_add_sei_message
actually use a pointer to the CodedBitstreamContext as opaque. It should
actually be neither, because it is unneeded (as is evidenced by the fact
that none of the free functions use this pointer at all) and because it
ties the unit's content to the lifetime of other objects, although a
refcounted buffer is supposed to have its own lifetime that only ends
when its reference count reaches zero. This problem manifests itself in
the pointer becoming dangling.
The pointer to the unit can become dangling if another unit is added to
the fragment later as happens in the bitstream filters; in this case,
the pointer can point to the wrong unit (if the fragment's unit array
needn't be relocated) or it can point to where the array was earlier.
It can also become dangling if the unit's content is meant to survive
the resetting of the fragment it was originally read with. This applies
to the extradata of H.264 and HEVC.
The pointer to the context can become dangling if the context is closed
before the content is freed. Although this doesn't seem to happen right
now, it could happen, in particular if one uses different
CodedBitstreamContexts for in- and output.
Signed-off-by: 's avatarAndreas Rheinhardt <andreas.rheinhardt@gmail.com>
      4e7e30bb
    • Michael Niedermayer's avatar
      avcodec/eatqi: Check for minimum frame size · 5ffb8e87
      Michael Niedermayer authored 
      The minimum header is 8 bytes, the smallest bitstream that is passed to
the MB decode code is 4 bytes

Fixes: Timeout (35sec -> 18sec)
Fixes: 15800/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_EATQI_fuzzer-5684154517159936

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpegReviewed-by: 's avatarPaul B Mahol <onemda@gmail.com>
Signed-off-by: 's avatarMichael Niedermayer <michael@niedermayer.cc>
      5ffb8e87