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https://github.com/FFmpeg/FFmpeg.git
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a247ac640d
Given that the AVCodec.next pointer has now been removed, most of the AVCodecs are not modified at all any more and can therefore be made const (as this patch does); the only exceptions are the very few codecs for external libraries that have a init_static_data callback. Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com> Signed-off-by: James Almer <jamrial@gmail.com>
149 lines
4.0 KiB
C
149 lines
4.0 KiB
C
/*
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* HCOM audio decoder
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "libavutil/intreadwrite.h"
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#include "avcodec.h"
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#include "get_bits.h"
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#include "internal.h"
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typedef struct HEntry {
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int16_t l, r;
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} HEntry;
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typedef struct HCOMContext {
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AVCodecContext *avctx;
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uint8_t first_sample;
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uint8_t sample;
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int dict_entries;
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int dict_entry;
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int delta_compression;
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HEntry *dict;
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} HCOMContext;
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static av_cold int hcom_init(AVCodecContext *avctx)
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{
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HCOMContext *s = avctx->priv_data;
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if (avctx->channels != 1) {
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av_log(avctx, AV_LOG_ERROR, "invalid number of channels\n");
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return AVERROR_INVALIDDATA;
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}
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if (avctx->extradata_size <= 7)
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return AVERROR_INVALIDDATA;
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s->dict_entries = AV_RB16(avctx->extradata);
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if (avctx->extradata_size < s->dict_entries * 4 + 7 ||
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s->dict_entries == 0)
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return AVERROR_INVALIDDATA;
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s->delta_compression = AV_RB32(avctx->extradata + 2);
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s->sample = s->first_sample = avctx->extradata[avctx->extradata_size - 1];
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s->dict = av_calloc(s->dict_entries, sizeof(*s->dict));
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if (!s->dict)
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return AVERROR(ENOMEM);
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for (int i = 0; i < s->dict_entries; i++) {
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s->dict[i].l = AV_RB16(avctx->extradata + 6 + 4 * i);
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s->dict[i].r = AV_RB16(avctx->extradata + 6 + 4 * i + 2);
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if (s->dict[i].l >= 0 &&
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(s->dict[i].l >= s->dict_entries ||
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s->dict[i].r >= s->dict_entries ||
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s->dict[i].r < 0 ))
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return AVERROR_INVALIDDATA;
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}
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if (s->dict[0].l < 0)
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return AVERROR_INVALIDDATA;
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avctx->sample_fmt = AV_SAMPLE_FMT_U8;
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s->dict_entry = 0;
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return 0;
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}
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static int hcom_decode(AVCodecContext *avctx, void *data,
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int *got_frame, AVPacket *pkt)
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{
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HCOMContext *s = avctx->priv_data;
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AVFrame *frame = data;
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GetBitContext gb;
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int ret, n = 0;
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if (pkt->size > INT16_MAX)
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return AVERROR_INVALIDDATA;
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frame->nb_samples = pkt->size * 8;
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if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
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return ret;
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if ((ret = init_get_bits8(&gb, pkt->data, pkt->size)) < 0)
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return ret;
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while (get_bits_left(&gb) > 0) {
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if (get_bits1(&gb))
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s->dict_entry = s->dict[s->dict_entry].r;
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else
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s->dict_entry = s->dict[s->dict_entry].l;
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if (s->dict[s->dict_entry].l < 0) {
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int16_t datum;
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datum = s->dict[s->dict_entry].r;
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if (!s->delta_compression)
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s->sample = 0;
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s->sample = (s->sample + datum) & 0xFF;
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frame->data[0][n++] = s->sample;
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s->dict_entry = 0;
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}
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}
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frame->nb_samples = n;
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*got_frame = 1;
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return pkt->size;
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}
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static av_cold int hcom_close(AVCodecContext *avctx)
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{
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HCOMContext *s = avctx->priv_data;
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av_freep(&s->dict);
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return 0;
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}
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const AVCodec ff_hcom_decoder = {
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.name = "hcom",
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.long_name = NULL_IF_CONFIG_SMALL("HCOM Audio"),
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.type = AVMEDIA_TYPE_AUDIO,
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.id = AV_CODEC_ID_HCOM,
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.priv_data_size = sizeof(HCOMContext),
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.init = hcom_init,
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.close = hcom_close,
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.decode = hcom_decode,
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.capabilities = AV_CODEC_CAP_DR1,
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.caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
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};
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