On Thu, 6 Mar 2025 at 14:31, Andreas Rheinhardt <andreas.rheinha...@outlook.com> wrote: > > Andreas Rheinhardt: > > Ramiro Polla: > >> On Tue, Mar 4, 2025 at 6:05 PM Andreas Rheinhardt > >> <andreas.rheinha...@outlook.com> wrote: > >>> Ramiro Polla: > >>>> > >>>> On 3/4/25 14:42, Andreas Rheinhardt wrote: > >>>>> (Mostly trivial) patches attached. A branch is at > >>>>> https://github.com/mkver/FFmpeg/tree/mpegvideo_misc > >>>> > >>>> > >>>> [PATCH 10/40] avcodec/mpegvideo_enc: Move default_mv_penalty to h261enc.c > >>>> > >>>>> diff --git a/libavcodec/h261enc.c b/libavcodec/h261enc.c > >>>>> index dabab9d80a..e33bf35a8a 100644 > >>>>> --- a/libavcodec/h261enc.c > >>>>> +++ b/libavcodec/h261enc.c > >>>>> @@ -46,6 +46,7 @@ static struct VLCLUT { > >>>>> uint16_t code; > >>>>> } vlc_lut[H261_MAX_RUN + 1][32 /* 0..2 * H261_MAX_LEN are used */]; > >>>>> > >>>>> +static uint8_t mv_penalty[MAX_FCODE + 1][MAX_DMV * 2 + 1]; > >>>>> static uint8_t uni_h261_rl_len [64 * 128]; > >>>>> static uint8_t uni_h261_rl_len_last[64 * 128]; > >>>>> static uint8_t h261_mv_codes[64][2]; > >>>>> @@ -370,6 +371,8 @@ av_cold int ff_h261_encode_init(MpegEncContext *s) > >>>>> s->max_qcoeff = 127; > >>>>> s->ac_esc_length = H261_ESC_LEN; > >>>>> > >>>>> + s->me.mv_penalty = mv_penalty; > >>>>> + > >>>>> s->intra_ac_vlc_length = s->inter_ac_vlc_length = > >>>>> uni_h261_rl_len; > >>>>> s->intra_ac_vlc_last_length = s->inter_ac_vlc_last_length = > >>>>> uni_h261_rl_len_last; > >>>>> ff_thread_once(&init_static_once, h261_encode_init_static); > >>>> > >>>> This global mv_penalty doesn't seem to be ever initialized; it could be > >>>> declared const. > >>> > >>> But then it would no longer be placed in .bss, but instead in .rodata > >>> and increase binary size. > >> > >> Wow, that's a huge array. > >> > >>>> But it also makes me think that whatever code is using this mv_penalty, > >>>> which is always set to zero, might be calculating things wrong. > >>>> > >>> > >>> It is obviously done to avoid branches for the codecs that matter. H.261 > >>> does not matter much. Apart from that, it is a very cheap workaround > >>> given that this table is .bss. > >> > >> Could you add some comments (either next to the declaration or the > >> commit message) to reflect this? (save space from .rodata, and this > >> being a noop for h.261, which doesn't matter that much) > >> > >>>> [PATCH 15/40] avcodec/ituh263enc: Make SVQ1+Snowenc stop calling > >>>> ff_h263_encode_init() > >>>> > >>>>> diff --git a/libavcodec/ituh263enc.c b/libavcodec/ituh263enc.c > >>>>> index 02da090ba4..8313b2c2c1 100644 > >>>>> --- a/libavcodec/ituh263enc.c > >>>>> +++ b/libavcodec/ituh263enc.c > >>>>> @@ -65,6 +65,127 @@ static uint8_t uni_h263_inter_rl_len [64*64*2*2]; > >>>> [...] > >>>>> +static av_cold void h263_encode_init_static(void) > >>>>> +{ > >>>>> + static uint8_t rl_intra_table[2][2 * MAX_RUN + MAX_LEVEL + 3]; > >>>>> + > >>>>> + ff_rl_init(&ff_rl_intra_aic, rl_intra_table); > >>>>> + ff_h263_init_rl_inter(); > >>>>> + > >>>>> + init_uni_h263_rl_tab(&ff_rl_intra_aic, uni_h263_intra_aic_rl_len); > >>>>> + init_uni_h263_rl_tab(&ff_h263_rl_inter, uni_h263_inter_rl_len); > >>>>> + > >>>>> + init_mv_penalty_and_fcode(); > >>>>> +} > >>>>> + > >>>>> +av_cold const uint8_t (*ff_h263_get_mv_penalty(void))[MAX_DMV*2+1] > >>>>> +{ > >>>>> + static AVOnce init_static_once = AV_ONCE_INIT; > >>>>> + > >>>>> + ff_thread_once(&init_static_once, h263_encode_init_static); > >>>>> + > >>>>> + return mv_penalty; > >>>>> +} > >>>>> + > >>>> > >>>> This approach kind of hides the rest of h263_encode_init_static() inside > >>>> ff_h263_get_mv_penalty(), so the name is a bit misleading. I'd expect > >>>> h263 to still call some init function and ff_h263_get_mv_penalty(), and > >>>> SVQ1 and Snow to only call ff_h263_get_mv_penalty(), which would only > >>>> take care of the mv_penalty table. > >>>> > >>> > >>> This would entail using another AVOnce etc. and this level of > >>> granularity is just not worth it. > >> > >> Ok. > >> > >>> The name is chosen for what it does for an outsider (i.e. from the > >>> perspective of svq1enc or snowenc, not the actual H.263 based encoders). > >> > >> I'm still not quite happy with the name and how it's used, but it's > >> good enough so I won't insist. > >> > >>>> [PATCH 20/40] avcodec/mpeg4video: Split ff_mpeg4_pred_dc() > >>>> > >>>>> diff --git a/libavcodec/mpeg4videoenc.c b/libavcodec/mpeg4videoenc.c > >>>>> index 64fb96a0cf..26f9b40ff7 100644 > >>>>> --- a/libavcodec/mpeg4videoenc.c > >>>>> +++ b/libavcodec/mpeg4videoenc.c > >>>>> @@ -806,8 +806,14 @@ void ff_mpeg4_encode_mb(MpegEncContext *s, > >>>>> int16_t block[6][64], > >>>>> const uint8_t *scan_table[6]; > >>>>> int i; > >>>>> > >>>>> - for (i = 0; i < 6; i++) > >>>>> - dc_diff[i] = ff_mpeg4_pred_dc(s, i, block[i][0], &dir[i], > >>>>> 1); > >>>>> + for (int i = 0; i < 6; i++) { > >>>> > >>>> Redeclaring i inside for. > >>> > >>> There are other loops which use this i as loop variable. The shadowing > >>> is IMO less bad than keeping loops in their current form (with iterators > >>> that don't have loop-scope). > >> > >> Agreed. I also prefer scoped iterators. > > > > I added a comment to #10 and modified #18 as described. I also changed > > #21 to protect the macro in parentheses and simplified the FF_RC_OFFSET > > macro in #31. Furthermore, there are now five more patches. All > > attached. https://github.com/mkver/FFmpeg/tree/mpegvideo_misc has been > > force-pushed. > > > Will apply this patchset (with the issues pointed out by Ramiro fixed) > tomorrow unless there are objections.
After the "Don't count errors from first thread twice" patch, there are some new UBSAN warnings. libavcodec/mpeg12dec.c:2264:37: runtime error: signed integer overflow: 2147483647 + 99 cannot be represented in type 'int' If we look around there are places where atomic_store(&s->error_count, INT_MAX); is done. I don't think this change caused the issue, because overflows would also happen before, but it looks like UBSAN doesn't instrument atomic variables, so it was hidden. Would you take a look? Thanks, Kacper _______________________________________________ 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".
