Previously, the code allowed overwriting on 16-aligned blocks, which was suitable when there were
no picture's virtual boundaries because both CTU sizes and strides were 16-aligned. However, with
picture's virtual boundaries, each CTU is divided into four ALF blocks, leading to potential issues
with overwriting later CTUs.
In cases involving picture virtual boundaries, each ALF block is 8-pixel aligned.
For luma, we consistently ensure an 8-aligned width. For chroma in 4:2:0 format,
we need to account for a 4-aligned width.
This avoids hardcoding any implementation-specific limitiations as
part of the API, and allows for future expandability.
This also allows API users to more conveniently convert the
values into floats without hardcoding specific conversion constants.
The API was committed a few days ago, so changing this field now
is within the realms of acceptable.
Currently, any unrecognised platform is treated as 32-bit. This should
detect *most* 64-bit platforms, namely LP64 and LLP64 ones.
Unfortunately this will not work for ILP32 ABIs on 64-bit ISAs, but
still better than nothing.
now that we are reading ext_mapping_idc as the upper 8 bits of
el_bit_depth_minus8 we need to use get_ue_golomb_long rather than
get_ue_golomb_31 for reading it
The C code for some pixel formats (rgb555, rgb565, rgb444, and monob)
was not converting the last pixels on widths not aligned to 8.
NOTE: the last pixel for odd widths is still not converted for any of
the pixel formats in the C code for yuv2rgb except for monob.
This allows ending up with a normal, non-fragmented file when
the file is finished, while keeping the file readable if writing
is aborted abruptly at any point. (Normally when writing a
mov/mp4 file, the unfinished file is completely useless unless it
is finished properly.)
This results in a file where the mdat atom contains (and hides)
all the moof atoms that were part of the fragmented file structure
initially.
Signed-off-by: Martin Storsjö <martin@martin.st>
These two fields are coded together into a single 16 bit integer with upper 8
bits for ext_mapping_idc and lower 8 bits for el_bit_depth_minus8.
Furthermore ext_mapping_idc has two components, upper 3 bits and lower 5 bits.
Co-authored-by: Niklas Haas <git@haasn.dev>
Signed-off-by: Niklas Haas <git@haasn.dev>
ffprobe is meant to generate parseable output, and if a field is present, it
should be printed even if it has a default value.
Signed-off-by: James Almer <jamrial@gmail.com>
These tables are supposed to contain the number of bits needed
to encode a given (run, level) pair. Yet the number of bits
for pairs needing the escape code was wrong (it only contained
the escape code and not the bits needed for run and level).
Furthermore, H.261 (a format with explicit end-of-block codes)
does not work well together with the RLTable API from rl.c:
The EOB code is the first one in ff_h261_rl_tcoeff's VLC table
and has a run value of zero. Therefore the result of get_rl_index()
is off by one for run == 0 and level values with explicit
(run, level) pair.
Fixing this necessitated changing the ref files of the
vsynth*-h261-trellis tests. Both filesizes as well as PSNR
decreased. If one used a qscale value of 11 for this test,
one would have received files with about the same size as
before this patch (with qscale 12), but with better PSNR.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
The RLTable API in rl.c is not well designed for codecs with
an explicit end-of-block code. ff_h261_rl_tcoeff's vlc has
the EOB code as first element (presumably so that the decoder
can check for it via "if (level == 0)") and this implies
that the indices returned by get_rl_index() are off by one
for run == 0 which is therefore explicitly checked.
This commit changes this by adding a simple LUT for the
values not requiring escaping. It is easy to directly
include the sign bit into this, so this has also been done.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
These must not be modified (even when they are initialized at runtime
and therefore modifiable).
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
It is a better place for it; no non-h263-based decoder needs
these functions any more (both H.261 and the error resilience
code recently stopped doing so).
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
It is an MPEG-4-only value; it is always five for the MPEG-4
encoder, so just hardcode this value and move the MpegEncContext
field to Mpeg4DecContext.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
The RV10 and RV20 decoders use ff_h263_decode_mb() and also the
H.263 DSP and VLCs. Despite not calling ff_h263_decode_frame(),
it is nevertheless beneficial to call ff_h263_decode_init()
to reduce code duplication.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
The error resilience code does not make up block coefficients
and therefore zeroes them in order to disable the IDCT.
But this can be done in a simpler manner, namely by setting
block_last_index to a negative value. Doing so also has
the advantage that the dct_unquantize functions are never even
called for those codecs that do not use ff_mpv_reconstruct_mb()
for ordinary decoding (namely RV-30/40 and the VC-1 family).
This approach would not work for intra macroblocks (there is always
at least one coefficient for them and therefore there is no check
for block_last_index for them), but this does not happen at all.
Add an assert for this.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
