[FFmpeg-devel] [PATCH 7/7] avcodec/aacdec_template: add support for 22.2 / channel_config 13

[Jan Ekström]

On Tue, Aug 18, 2020 at 12:17 PM Paul B Mahol <onemda at gmail.com> wrote:
>
> I think there is open bug report about SEGV regarding this commit on trac.
>
> Please revert or fix ASAP!
>

Thank you for letting me know about this. I will take a look at this
after work. Please do not yell at me, I am not your enemy.

Jan

> On 8/16/20, Michael Niedermayer <michael at niedermayer.cc> wrote:
> > On Sat, Aug 01, 2020 at 02:07:30PM +0300, Jan Ekström wrote:
> >> ---
> >>  libavcodec/aacdec_template.c | 89 +++++++++++++++++++++++++++++++-----
> >>  1 file changed, 78 insertions(+), 11 deletions(-)
> >>
> >> diff --git a/libavcodec/aacdec_template.c b/libavcodec/aacdec_template.c
> >> index 21db12fdab..8c5048cc13 100644
> >> --- a/libavcodec/aacdec_template.c
> >> +++ b/libavcodec/aacdec_template.c
> >> @@ -387,17 +387,77 @@ static uint64_t sniff_channel_order(uint8_t
> >> (*layout_map)[3], int tags)
> >>          i++;
> >>      }
> >>
> >> -    // Must choose a stable sort
> >> +    // The previous checks would end up at 8 at this point for 22.2
> >> +    if (tags == 16 && i == 8) {
> >> +        e2c_vec[i] = (struct elem_to_channel) {
> >> +            .av_position  = AV_CH_TOP_FRONT_CENTER,
> >> +            .syn_ele      = layout_map[i][0],
> >> +            .elem_id      = layout_map[i][1],
> >> +            .aac_position = layout_map[i][2]
> >> +        }; i++;
> >> +        i += assign_pair(e2c_vec, layout_map, i,
> >> +                         AV_CH_TOP_FRONT_LEFT,
> >> +                         AV_CH_TOP_FRONT_RIGHT,
> >> +                         AAC_CHANNEL_FRONT);
> >> +        i += assign_pair(e2c_vec, layout_map, i,
> >> +                         AV_CH_TOP_SIDE_LEFT,
> >> +                         AV_CH_TOP_SIDE_RIGHT,
> >> +                         AAC_CHANNEL_SIDE);
> >> +        e2c_vec[i] = (struct elem_to_channel) {
> >> +            .av_position  = AV_CH_TOP_CENTER,
> >> +            .syn_ele      = layout_map[i][0],
> >> +            .elem_id      = layout_map[i][1],
> >> +            .aac_position = layout_map[i][2]
> >> +        }; i++;
> >> +        i += assign_pair(e2c_vec, layout_map, i,
> >> +                         AV_CH_TOP_BACK_LEFT,
> >> +                         AV_CH_TOP_BACK_RIGHT,
> >> +                         AAC_CHANNEL_BACK);
> >> +        e2c_vec[i] = (struct elem_to_channel) {
> >> +            .av_position  = AV_CH_TOP_BACK_CENTER,
> >> +            .syn_ele      = layout_map[i][0],
> >
> > Does this code assume all types are CPE ?
> > because if thats not true i can exceed the tags
> >
> >
> >> +            .elem_id      = layout_map[i][1],
> >> +            .aac_position = layout_map[i][2]
> >> +        }; i++;
> >> +        e2c_vec[i] = (struct elem_to_channel) {
> >> +            .av_position  = AV_CH_BOTTOM_FRONT_CENTER,
> >> +            .syn_ele      = layout_map[i][0],
> >> +            .elem_id      = layout_map[i][1],
> >> +            .aac_position = layout_map[i][2]
> >> +        }; i++;
> >> +        i += assign_pair(e2c_vec, layout_map, i,
> >> +                         AV_CH_BOTTOM_FRONT_LEFT,
> >> +                         AV_CH_BOTTOM_FRONT_RIGHT,
> >> +                         AAC_CHANNEL_FRONT);
> >> +    }
> >> +
> >>      total_non_cc_elements = n = i;
> >> -    do {
> >> -        int next_n = 0;
> >> -        for (i = 1; i < n; i++)
> >> -            if (e2c_vec[i - 1].av_position > e2c_vec[i].av_position) {
> >> -                FFSWAP(struct elem_to_channel, e2c_vec[i - 1],
> >> e2c_vec[i]);
> >> -                next_n = i;
> >> -            }
> >> -        n = next_n;
> >> -    } while (n > 0);
> >> +
> >> +    if (tags == 16 && total_non_cc_elements == 16) {
> >> +        // For 22.2 reorder the result as needed
> >> +        FFSWAP(struct elem_to_channel, e2c_vec[2], e2c_vec[0]);   // FL &
> >> FR first (final), FC third
> >> +        FFSWAP(struct elem_to_channel, e2c_vec[2], e2c_vec[1]);   // FC
> >> second (final), FLc & FRc third
> >> +        FFSWAP(struct elem_to_channel, e2c_vec[6], e2c_vec[2]);   // LFE1
> >> third (final), FLc & FRc seventh
> >> +        FFSWAP(struct elem_to_channel, e2c_vec[4], e2c_vec[3]);   // BL &
> >> BR fourth (final), SiL & SiR fifth
> >> +        FFSWAP(struct elem_to_channel, e2c_vec[6], e2c_vec[4]);   // FLc
> >> & FRc fifth (final), SiL & SiR seventh
> >> +        FFSWAP(struct elem_to_channel, e2c_vec[7], e2c_vec[6]);   // LFE2
> >> seventh (final), SiL & SiR eight (final)
> >> +        FFSWAP(struct elem_to_channel, e2c_vec[9], e2c_vec[8]);   // TpFL
> >> & TpFR ninth (final), TFC tenth (final)
> >> +        FFSWAP(struct elem_to_channel, e2c_vec[11], e2c_vec[10]); // TC
> >> eleventh (final), TpSiL & TpSiR twelth
> >> +        FFSWAP(struct elem_to_channel, e2c_vec[12], e2c_vec[11]); // TpBL
> >> & TpBR twelth (final), TpSiL & TpSiR thirteenth (final)
> >
> > Does this not need to check the assumtations from the comments ?
> >
> > thx
> >
> > [...]
> > --
> > Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
> >
> > Awnsering whenever a program halts or runs forever is
> > On a turing machine, in general impossible (turings halting problem).
> > On any real computer, always possible as a real computer has a finite
> > number
> > of states N, and will either halt in less than N cycles or never halt.
> >
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