Add a `constexpr` constructor and several `constexpr` methods to
construct a DecoderPlugin at compile time, in a way which allows
adding new methods later without having to edit each plugin.
Eliminates a number of allocations, because callers don't need to copy
the strings to a newly allocated buffer only to null-terminate them.
And most callers don't need to have a null-terminated string.
Since we now don't duplicate all items, we can easily remove the 64kB
limit from OpusReader::ReadString() and instead silently ignore and
skip all strings which are longer than 4 kB.
This fixes a tag duplication bug with Opus file containing a very long
`METADATA_BLOCK_PICTURE` tag, which occurred because the Opus plugin
returned false after parsing all tags, and then the MPD core fell back
to FFmpeg which scanned the tags again.
Re-add build support for the fixed-point Vorbis (Tremor) decoder, which
was dropped when switching from Autotools to Meson.
Note, that it is not possible to build both, the Vorbis and the Tremor
decoder.
Closes: #405
Since we switched from autotools to Meson in commit
94592c1406, we don't need to include
`config.h` early to properly enable large file support. Meson passes
the required macros on the compiler command line instead of defining
them in `config.h`.
This means we can include `config.h` at any time, whenever we want to
check its macros, and there are no ordering constraints.
`AVCodecParameters` contains values from the codec detected by
avformat_find_stream_info(), but after avcodec_open2(), a different
codec might be selected with a different `AVSampleFormat`. This leads
to misinterpretation of data returned from FFmpeg, leading to random
noise or silence.
This was observed with FFmpeg 4.0.2 and a TS container file containing
MP2. A mp3-float codec was detected returning `AV_SAMPLE_FMT_FLTP`,
but finally the `mpegaudiodec_fixed.c` was used, returning
`AV_SAMPLE_FMT_S16`.
By using the audio format from `AVCodecContext`, we ensure that MPD
and FFmpeg always agree on the actual audio format in the buffer.
This removes the FFmpeg bug workaround from commit e1b032cbad which I
assume is obsolete after 7 years.
Fixes#380
