The presentation time in fMP4 is calculated by adding and subtracting
3 values. All 3 values are currently converted to microseconds first
before the calculation, leading to rounding errors. The rounding errors
can be avoided by doing the conversion to microseconds as the last step.
For example:
In timescale 96000: 8008+8008-16016 = 0
Rounding to us first: 83416+83416-166833=-1
#minor-release
PiperOrigin-RevId: 406809844
Test file produced with:
$ MP4Box -add "sample.mp4#video:colr=nclc,1,1,1" -new sample_18byte_nclx_colr.mp4
And then manually changing the `nclc` bytes to `nclx`.
This produces an 18-byte `colr` box with type `nclx`. The bitstream of
this file does not contain HDR content, so the file itself is invalid
for playback with a real decoder, but adding the box is enough to test
the extractor change in this commit.
(aside: MP4Box will let you pass `nclx`, but it requires 4 parameters, i.e. it
requires the full_range_flag to be set, resulting in a valid 19-byte colr box)
#minor-release
Issue: #9332
PiperOrigin-RevId: 405842520
- This CL does not introduce functional changes.
- This change will allow searching for the clli box while
parsing the mdcv box in order to construct the HDR
static info contained in ColorInfo.
#minor-release
PiperOrigin-RevId: 405656499
When ExtractorInput.getLength() returns a defined length, the
SubtitleExtractor will create a buffer of the same length, call
ExtractorInput.read() until it has read the input bytes, plus one more
time where ExtractorInput.read() returns RESULT_END_OF_INPUT. The last
call to ExtractorInput.read() however will make the SubtitleExtractor to
increase its buffer (including a copy) unnecessarily.
This change makes the SubtitleExtractor avoid calling
ExtractorInput.read() if the expected number of bytes have already
been read, so that the internal buffer does not grow.
PiperOrigin-RevId: 402583610
Before this change, the SubtitleExtractor did not mark the limit
of the input buffer, thus the SubtitleDecoder attempted to decode
more bytes. If the subtitle file had a new line at the end, this
bug would make the SubtitleDecoder append an line break after the
last subtitle.
PiperOrigin-RevId: 402523039
The previous implementation did the following (after skipping any ID3
headers at the start of the stream):
1. Skip forward byte-by-byte looking for a sync word (0xFFF)
2. Assume this indicates the start of an ADTS frame and read the size
a) If frameSize <= 6 immediately return false
3. Skip forward by frameSize and expect to find another ADTS sync word
(with no further scanning).
b) If we find one, great! Loop from step 2.
a) If we don't find one then assume the **last** sync word we found
wasn't actually one, so loop from step 1 starting one extra byte
into the stream. This means we're looking for a sync word we would
have skipped over in step 3.
The asymmetry here comes from the different handling of frameSize <= 6
(immediately return false) and frameSize being 'wrong because it doesn't
lead to another sync word' (scan the file again from the beginning for
alternative sync words).
With this change both these cases are handled symmetrically (always scan
for alternative sync words). Step 2a) becomes the same as 3b): Loop back
to the beginning of the stream with an incremented offset and scan for
another sync word.
#minor-release
PiperOrigin-RevId: 397285756
SubtitleExtractor is using IndexSeekMap with only one position to
indicate that its output is seekable. SubtitleExtractor is keeping Cues
in memory anyway so more seek points are not needed. SubtitleExtractor
gets notified about seek occurrence through seek() method. Inside that
method extractor saves seekTimeUs, and on the next call to read()
extractor outputs all cues that should be displayed at this time and
later.
PiperOrigin-RevId: 395477127
Simplifies the SubtitleExtractor implementation. Makes the extractor
more aligned with the Extractor interface documentation by removing
STATE_DECODING in which extractor was doing nothing in term of input
and output while returning RESULT_CONTINUE at the same time.
PiperOrigin-RevId: 395267468
This typically happens if there's a discontinuity in the stream.
It's better to say we don't know, than it is to return a negative
position.
Issue: #8346
#exofixit
#minor-release
PiperOrigin-RevId: 395224088
Extractor was not calling endTracks() and seekMap() on the
extractorOutput which are required to finish the preparation.
At that point extractor does not support seeking.
PiperOrigin-RevId: 393994848
