On Sat, Jun 8, 2024 at 9:58 PM Andreas Rheinhardt <
andreas.rheinha...@outlook.com> wrote:
> Vittorio Giovara:
> > On Sat, Jun 8, 2024 at 9:45 PM Andreas Rheinhardt <
> > andreas.rheinha...@outlook.com> wrote:
> >
> >> Andreas Rheinhardt:
> >>> Signed-off-by: Andreas Rheinhardt <andreas.rheinha...@outlook.com>
> >>> ---
> >>> libavcodec/dnxhdenc.c | 33 +++++++++++++++++----------------
> >>> 1 file changed, 17 insertions(+), 16 deletions(-)
> >>>
> >>> diff --git a/libavcodec/dnxhdenc.c b/libavcodec/dnxhdenc.c
> >>> index 0cb25d7714..4760a2932c 100644
> >>> --- a/libavcodec/dnxhdenc.c
> >>> +++ b/libavcodec/dnxhdenc.c
> >>> @@ -559,7 +559,7 @@ static int dnxhd_write_header(AVCodecContext
> *avctx,
> >> uint8_t *buf)
> >>> return 0;
> >>> }
> >>>
> >>> -static av_always_inline void dnxhd_encode_dc(DNXHDEncContext *ctx, int
> >> diff)
> >>> +static av_always_inline void dnxhd_encode_dc(PutBitContext *pb,
> >> DNXHDEncContext *ctx, int diff)
> >>> {
> >>> int nbits;
> >>> if (diff < 0) {
> >>> @@ -568,19 +568,19 @@ static av_always_inline void
> >> dnxhd_encode_dc(DNXHDEncContext *ctx, int diff)
> >>> } else {
> >>> nbits = av_log2_16bit(2 * diff);
> >>> }
> >>> - put_bits(&ctx->m.pb, ctx->cid_table->dc_bits[nbits] + nbits,
> >>> + put_bits(pb, ctx->cid_table->dc_bits[nbits] + nbits,
> >>> (ctx->cid_table->dc_codes[nbits] << nbits) +
> >>> av_mod_uintp2(diff, nbits));
> >>> }
> >>>
> >>> static av_always_inline
> >>> -void dnxhd_encode_block(DNXHDEncContext *ctx, int16_t *block,
> >>> - int last_index, int n)
> >>> +void dnxhd_encode_block(PutBitContext *pb, DNXHDEncContext *ctx,
> >>> + int16_t *block, int last_index, int n)
> >>> {
> >>> int last_non_zero = 0;
> >>> int slevel, i, j;
> >>>
> >>> - dnxhd_encode_dc(ctx, block[0] - ctx->m.last_dc[n]);
> >>> + dnxhd_encode_dc(pb, ctx, block[0] - ctx->m.last_dc[n]);
> >>> ctx->m.last_dc[n] = block[0];
> >>>
> >>> for (i = 1; i <= last_index; i++) {
> >>> @@ -589,14 +589,14 @@ void dnxhd_encode_block(DNXHDEncContext *ctx,
> >> int16_t *block,
> >>> if (slevel) {
> >>> int run_level = i - last_non_zero - 1;
> >>> int rlevel = slevel * (1 << 1) | !!run_level;
> >>> - put_bits(&ctx->m.pb, ctx->vlc_bits[rlevel],
> >> ctx->vlc_codes[rlevel]);
> >>> + put_bits(pb, ctx->vlc_bits[rlevel],
> ctx->vlc_codes[rlevel]);
> >>> if (run_level)
> >>> - put_bits(&ctx->m.pb, ctx->run_bits[run_level],
> >>> + put_bits(pb, ctx->run_bits[run_level],
> >>> ctx->run_codes[run_level]);
> >>> last_non_zero = i;
> >>> }
> >>> }
> >>> - put_bits(&ctx->m.pb, ctx->vlc_bits[0], ctx->vlc_codes[0]); // EOB
> >>> + put_bits(pb, ctx->vlc_bits[0], ctx->vlc_codes[0]); // EOB
> >>> }
> >>>
> >>> static av_always_inline
> >>> @@ -879,9 +879,10 @@ static int dnxhd_encode_thread(AVCodecContext
> >> *avctx, void *arg,
> >>> int jobnr, int threadnr)
> >>> {
> >>> DNXHDEncContext *ctx = avctx->priv_data;
> >>> + PutBitContext pb0, *const pb = &pb0;
> >>> int mb_y = jobnr, mb_x;
> >>> ctx = ctx->thread[threadnr];
> >>> - init_put_bits(&ctx->m.pb, (uint8_t *)arg + ctx->data_offset +
> >> ctx->slice_offs[jobnr],
> >>> + init_put_bits(pb, (uint8_t *)arg + ctx->data_offset +
> >> ctx->slice_offs[jobnr],
> >>> ctx->slice_size[jobnr]);
> >>>
> >>> ctx->m.last_dc[0] =
> >>> @@ -892,8 +893,8 @@ static int dnxhd_encode_thread(AVCodecContext
> >> *avctx, void *arg,
> >>> int qscale = ctx->mb_qscale[mb];
> >>> int i;
> >>>
> >>> - put_bits(&ctx->m.pb, 11, qscale);
> >>> - put_bits(&ctx->m.pb, 1, avctx->pix_fmt ==
> AV_PIX_FMT_YUV444P10);
> >>> + put_bits(pb, 11, qscale);
> >>> + put_bits(pb, 1, avctx->pix_fmt == AV_PIX_FMT_YUV444P10);
> >>>
> >>> dnxhd_get_blocks(ctx, mb_x, mb_y);
> >>>
> >>> @@ -904,13 +905,13 @@ static int dnxhd_encode_thread(AVCodecContext
> >> *avctx, void *arg,
> >>> ctx->is_444 ? (((i >>
> >> 1) % 3) < 1 ? 0 : 4): 4 & (2*i),
> >>> qscale, &overflow);
> >>>
> >>> - dnxhd_encode_block(ctx, block, last_index, n);
> >>> + dnxhd_encode_block(pb, ctx, block, last_index, n);
> >>> }
> >>> }
> >>> - if (put_bits_count(&ctx->m.pb) & 31)
> >>> - put_bits(&ctx->m.pb, 32 - (put_bits_count(&ctx->m.pb) & 31),
> 0);
> >>> - flush_put_bits(&ctx->m.pb);
> >>> - memset(put_bits_ptr(&ctx->m.pb), 0, put_bytes_left(&ctx->m.pb,
> 0));
> >>> + if (put_bits_count(pb) & 31)
> >>> + put_bits(pb, 32 - (put_bits_count(pb) & 31), 0);
> >>> + flush_put_bits(pb);
> >>> + memset(put_bits_ptr(pb), 0, put_bytes_left(pb, 0));
> >>> return 0;
> >>> }
> >>>
> >>
> >> Will apply this patchset tomorrow unless there are objections.
> >>
> >
> > No objections, but what is the rationale here? Just reducing variables
> > scope?
>
> Avoiding usage of MpegEncContext (which is only supposed to be used for
> quantization dsp functions). And putting transient variables on the
> stack is always good practice (unless they are too big). It also has the
> advantage that the compiler can better reason about them, because their
> address does not escape (currently, the compiler has to presume that all
> the dsp calls in dnxhd_get_blocks() can modify the PutBitContext).
>
Thanks for the explanation - it would be great to have this text in the
commit log too!
--
Vittorio
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
To unsubscribe, visit link above, or email
ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
