| Message ID | 20231126012858.40388-3-jamrial@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | avformat: introduce AVStreamGroup | expand |
| Context | Check | Description |
|---|---|---|
| andriy/make_x86 | success | Make finished |
| andriy/make_fate_x86 | success | Make fate finished |
On 11/25/23 20:28, James Almer wrote: > Signed-off-by: James Almer <jamrial@gmail.com> > --- > libavcodec/bitstream.h | 2 ++ > libavcodec/bitstream_template.h | 22 ++++++++++++++++++++++ > libavcodec/get_bits.h | 23 +++++++++++++++++++++++ > 3 files changed, 47 insertions(+) > Out of curiosity, why do this (and the avio version) have to be global? What are they used for other than the iamf demuxer? Would it make sense to have a static inline read_leb function defined in iamf.c? - Leo Izen (Traneptora)
On 11/26/2023 10:40 AM, Leo Izen wrote: > On 11/25/23 20:28, James Almer wrote: >> Signed-off-by: James Almer <jamrial@gmail.com> >> --- >> libavcodec/bitstream.h | 2 ++ >> libavcodec/bitstream_template.h | 22 ++++++++++++++++++++++ >> libavcodec/get_bits.h | 23 +++++++++++++++++++++++ >> 3 files changed, 47 insertions(+) >> > > Out of curiosity, why do this (and the avio version) have to be global? > What are they used for other than the iamf demuxer? Would it make sense > to have a static inline read_leb function defined in iamf.c? They can be used by the av1 modules too, and potentially other formats in the future using the OBU encapsulation.
> add get_leb()
Do you expect people to understand what this means?
On Thu, Nov 30, 2023 at 11:40 AM Anton Khirnov <anton@khirnov.net> wrote: > > add get_leb() > > Do you expect people to understand what this means? > get_leb() : get little-endian bits. > -- > Anton Khirnov > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe". >
On 11/30/2023 7:40 AM, Anton Khirnov wrote: >> add get_leb() > > Do you expect people to understand what this means? Will add "Read an unsigned integer coded as a variable number of little-endian bytes".
diff --git a/libavcodec/bitstream.h b/libavcodec/bitstream.h index 35b7873b9c..17f8a5da83 100644 --- a/libavcodec/bitstream.h +++ b/libavcodec/bitstream.h @@ -103,6 +103,7 @@ # define bits_apply_sign bits_apply_sign_le # define bits_read_vlc bits_read_vlc_le # define bits_read_vlc_multi bits_read_vlc_multi_le +# define bits_read_leb bits_read_leb_le #elif defined(BITS_DEFAULT_BE) @@ -132,6 +133,7 @@ # define bits_apply_sign bits_apply_sign_be # define bits_read_vlc bits_read_vlc_be # define bits_read_vlc_multi bits_read_vlc_multi_be +# define bits_read_leb bits_read_leb_be #endif diff --git a/libavcodec/bitstream_template.h b/libavcodec/bitstream_template.h index 4f3d07275f..86cbab288e 100644 --- a/libavcodec/bitstream_template.h +++ b/libavcodec/bitstream_template.h @@ -562,6 +562,28 @@ static inline int BS_FUNC(read_vlc_multi)(BSCTX *bc, uint8_t dst[8], return ret; } +static inline unsigned BS_FUNC(read_leb)(BSCTX *bc) { + int more, i = 0; + unsigned leb = 0; + + do { + unsigned bits; + int byte = BS_FUNC(read)(bc, 8); + more = byte & 0x80; + bits = byte & 0x7f; + if (i <= 3 || (i == 4 && bits < (1 << 4))) { + leb |= bits << (i * 7); + } else if (bits) { // leb > UINT_MAX + leb |= (bits & 0xF) << (i * 7); + break; + } + if (++i == 8 && more) + break; // invalid leb + } while (more); + + return leb; +} + #undef BSCTX #undef BS_FUNC #undef BS_JOIN3 diff --git a/libavcodec/get_bits.h b/libavcodec/get_bits.h index cfcf97c021..cf9d5129b5 100644 --- a/libavcodec/get_bits.h +++ b/libavcodec/get_bits.h @@ -94,6 +94,7 @@ typedef BitstreamContext GetBitContext; #define align_get_bits bits_align #define get_vlc2 bits_read_vlc #define get_vlc_multi bits_read_vlc_multi +#define get_leb bits_read_leb #define init_get_bits8_le(s, buffer, byte_size) bits_init8_le((BitstreamContextLE*)s, buffer, byte_size) #define get_bits_le(s, n) bits_read_le((BitstreamContextLE*)s, n) @@ -710,6 +711,28 @@ static inline int skip_1stop_8data_bits(GetBitContext *gb) return 0; } +static inline unsigned get_leb(GetBitContext *gb) { + int more, i = 0; + unsigned leb = 0; + + do { + unsigned bits; + int byte = get_bits(gb, 8); + more = byte & 0x80; + bits = byte & 0x7f; + if (i <= 3 || (i == 4 && bits < (1 << 4))) { + leb |= bits << (i * 7); + } else if (bits) { // leb > UINT_MAX + leb |= (bits & 0xF) << (i * 7); + break; + } + if (++i == 8 && more) + break; // invalid leb + } while (more); + + return leb; +} + #endif // CACHED_BITSTREAM_READER #endif /* AVCODEC_GET_BITS_H */
Signed-off-by: James Almer <jamrial@gmail.com> --- libavcodec/bitstream.h | 2 ++ libavcodec/bitstream_template.h | 22 ++++++++++++++++++++++ libavcodec/get_bits.h | 23 +++++++++++++++++++++++ 3 files changed, 47 insertions(+)