319 lines
11 KiB
C
319 lines
11 KiB
C
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/*
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* LPCM codecs for PCM formats found in Video DVD streams
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* Copyright (c) 2013 Christian Schmidt
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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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/**
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* @file
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* LPCM codecs for PCM formats found in Video DVD streams
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*/
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#include "avcodec.h"
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#include "bytestream.h"
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#include "internal.h"
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typedef struct PCMDVDContext {
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uint32_t last_header; // Cached header to see if parsing is needed
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int block_size; // Size of a block of samples in bytes
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int last_block_size; // Size of the last block of samples in bytes
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int samples_per_block; // Number of samples per channel per block
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int groups_per_block; // Number of 20/24-bit sample groups per block
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uint8_t *extra_samples; // Pointer to leftover samples from a frame
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int extra_sample_count; // Number of leftover samples in the buffer
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} PCMDVDContext;
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static av_cold int pcm_dvd_decode_init(AVCodecContext *avctx)
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{
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PCMDVDContext *s = avctx->priv_data;
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/* Invalid header to force parsing of the first header */
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s->last_header = -1;
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/* reserve space for 8 channels, 3 bytes/sample, 4 samples/block */
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if (!(s->extra_samples = av_malloc(8 * 3 * 4)))
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return AVERROR(ENOMEM);
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return 0;
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}
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static av_cold int pcm_dvd_decode_uninit(AVCodecContext *avctx)
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{
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PCMDVDContext *s = avctx->priv_data;
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av_freep(&s->extra_samples);
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return 0;
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}
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static int pcm_dvd_parse_header(AVCodecContext *avctx, const uint8_t *header)
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{
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/* no traces of 44100 and 32000Hz in any commercial software or player */
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static const uint32_t frequencies[4] = { 48000, 96000, 44100, 32000 };
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PCMDVDContext *s = avctx->priv_data;
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int header_int = (header[0] & 0xe0) | (header[1] << 8) | (header[2] << 16);
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/* early exit if the header didn't change apart from the frame number */
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if (s->last_header == header_int)
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return 0;
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s->last_header = -1;
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if (avctx->debug & FF_DEBUG_PICT_INFO)
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av_log(avctx, AV_LOG_DEBUG, "pcm_dvd_parse_header: header = %02x%02x%02x\n",
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header[0], header[1], header[2]);
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/*
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* header[0] emphasis (1), muse(1), reserved(1), frame number(5)
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* header[1] quant (2), freq(2), reserved(1), channels(3)
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* header[2] dynamic range control (0x80 = off)
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*/
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/* Discard potentially existing leftover samples from old channel layout */
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s->extra_sample_count = 0;
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/* get the sample depth and derive the sample format from it */
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avctx->bits_per_coded_sample = 16 + (header[1] >> 6 & 3) * 4;
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if (avctx->bits_per_coded_sample == 28) {
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av_log(avctx, AV_LOG_ERROR,
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"PCM DVD unsupported sample depth %i\n",
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avctx->bits_per_coded_sample);
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return AVERROR_INVALIDDATA;
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}
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avctx->sample_fmt = avctx->bits_per_coded_sample == 16 ? AV_SAMPLE_FMT_S16
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: AV_SAMPLE_FMT_S32;
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avctx->bits_per_raw_sample = avctx->bits_per_coded_sample;
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/* get the sample rate */
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avctx->sample_rate = frequencies[header[1] >> 4 & 3];
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/* get the number of channels */
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avctx->channels = 1 + (header[1] & 7);
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/* calculate the bitrate */
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avctx->bit_rate = avctx->channels *
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avctx->sample_rate *
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avctx->bits_per_coded_sample;
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/* 4 samples form a group in 20/24-bit PCM on DVD Video.
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* A block is formed by the number of groups that are
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* needed to complete a set of samples for each channel. */
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if (avctx->bits_per_coded_sample == 16) {
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s->samples_per_block = 1;
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s->block_size = avctx->channels * 2;
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} else {
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switch (avctx->channels) {
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case 1:
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case 2:
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case 4:
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/* one group has all the samples needed */
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s->block_size = 4 * avctx->bits_per_coded_sample / 8;
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s->samples_per_block = 4 / avctx->channels;
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s->groups_per_block = 1;
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break;
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case 8:
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/* two groups have all the samples needed */
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s->block_size = 8 * avctx->bits_per_coded_sample / 8;
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s->samples_per_block = 1;
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s->groups_per_block = 2;
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break;
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default:
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/* need avctx->channels groups */
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s->block_size = 4 * avctx->channels *
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avctx->bits_per_coded_sample / 8;
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s->samples_per_block = 4;
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s->groups_per_block = avctx->channels;
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break;
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}
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}
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if (avctx->debug & FF_DEBUG_PICT_INFO)
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ff_dlog(avctx,
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"pcm_dvd_parse_header: %d channels, %d bits per sample, %d Hz, %"PRId64" bit/s\n",
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avctx->channels, avctx->bits_per_coded_sample,
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avctx->sample_rate, avctx->bit_rate);
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s->last_header = header_int;
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return 0;
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}
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static void *pcm_dvd_decode_samples(AVCodecContext *avctx, const uint8_t *src,
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void *dst, int blocks)
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{
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PCMDVDContext *s = avctx->priv_data;
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int16_t *dst16 = dst;
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int32_t *dst32 = dst;
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GetByteContext gb;
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int i;
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uint8_t t;
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bytestream2_init(&gb, src, blocks * s->block_size);
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switch (avctx->bits_per_coded_sample) {
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case 16: {
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#if HAVE_BIGENDIAN
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bytestream2_get_buffer(&gb, dst16, blocks * s->block_size);
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dst16 += blocks * s->block_size / 2;
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#else
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int samples = blocks * avctx->channels;
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do {
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*dst16++ = bytestream2_get_be16u(&gb);
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} while (--samples);
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#endif
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return dst16;
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}
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case 20:
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if (avctx->channels == 1) {
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do {
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for (i = 2; i; i--) {
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dst32[0] = bytestream2_get_be16u(&gb) << 16;
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dst32[1] = bytestream2_get_be16u(&gb) << 16;
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t = bytestream2_get_byteu(&gb);
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*dst32++ += (t & 0xf0) << 8;
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*dst32++ += (t & 0x0f) << 12;
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}
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} while (--blocks);
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} else {
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do {
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for (i = s->groups_per_block; i; i--) {
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dst32[0] = bytestream2_get_be16u(&gb) << 16;
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dst32[1] = bytestream2_get_be16u(&gb) << 16;
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dst32[2] = bytestream2_get_be16u(&gb) << 16;
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dst32[3] = bytestream2_get_be16u(&gb) << 16;
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t = bytestream2_get_byteu(&gb);
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*dst32++ += (t & 0xf0) << 8;
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*dst32++ += (t & 0x0f) << 12;
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t = bytestream2_get_byteu(&gb);
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*dst32++ += (t & 0xf0) << 8;
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*dst32++ += (t & 0x0f) << 12;
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}
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} while (--blocks);
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}
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return dst32;
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case 24:
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if (avctx->channels == 1) {
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do {
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for (i = 2; i; i--) {
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dst32[0] = bytestream2_get_be16u(&gb) << 16;
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dst32[1] = bytestream2_get_be16u(&gb) << 16;
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*dst32++ += bytestream2_get_byteu(&gb) << 8;
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*dst32++ += bytestream2_get_byteu(&gb) << 8;
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}
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} while (--blocks);
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} else {
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do {
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for (i = s->groups_per_block; i; i--) {
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dst32[0] = bytestream2_get_be16u(&gb) << 16;
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dst32[1] = bytestream2_get_be16u(&gb) << 16;
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dst32[2] = bytestream2_get_be16u(&gb) << 16;
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dst32[3] = bytestream2_get_be16u(&gb) << 16;
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*dst32++ += bytestream2_get_byteu(&gb) << 8;
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*dst32++ += bytestream2_get_byteu(&gb) << 8;
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*dst32++ += bytestream2_get_byteu(&gb) << 8;
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*dst32++ += bytestream2_get_byteu(&gb) << 8;
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}
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} while (--blocks);
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}
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return dst32;
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default:
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return NULL;
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}
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}
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static int pcm_dvd_decode_frame(AVCodecContext *avctx, void *data,
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int *got_frame_ptr, AVPacket *avpkt)
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{
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AVFrame *frame = data;
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const uint8_t *src = avpkt->data;
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int buf_size = avpkt->size;
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PCMDVDContext *s = avctx->priv_data;
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int retval;
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int blocks;
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void *dst;
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if (buf_size < 3) {
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av_log(avctx, AV_LOG_ERROR, "PCM packet too small\n");
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return AVERROR_INVALIDDATA;
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}
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if ((retval = pcm_dvd_parse_header(avctx, src)))
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return retval;
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if (s->last_block_size && s->last_block_size != s->block_size) {
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av_log(avctx, AV_LOG_WARNING, "block_size has changed %d != %d\n", s->last_block_size, s->block_size);
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s->extra_sample_count = 0;
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}
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s->last_block_size = s->block_size;
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src += 3;
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buf_size -= 3;
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blocks = (buf_size + s->extra_sample_count) / s->block_size;
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/* get output buffer */
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frame->nb_samples = blocks * s->samples_per_block;
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if ((retval = ff_get_buffer(avctx, frame, 0)) < 0)
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return retval;
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dst = frame->data[0];
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/* consume leftover samples from last packet */
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if (s->extra_sample_count) {
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int missing_samples = s->block_size - s->extra_sample_count;
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if (buf_size >= missing_samples) {
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memcpy(s->extra_samples + s->extra_sample_count, src,
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missing_samples);
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dst = pcm_dvd_decode_samples(avctx, s->extra_samples, dst, 1);
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src += missing_samples;
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buf_size -= missing_samples;
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s->extra_sample_count = 0;
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blocks--;
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} else {
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/* new packet still doesn't have enough samples */
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memcpy(s->extra_samples + s->extra_sample_count, src, buf_size);
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s->extra_sample_count += buf_size;
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return avpkt->size;
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}
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}
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/* decode remaining complete samples */
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if (blocks) {
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pcm_dvd_decode_samples(avctx, src, dst, blocks);
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buf_size -= blocks * s->block_size;
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}
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/* store leftover samples */
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if (buf_size) {
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src += blocks * s->block_size;
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memcpy(s->extra_samples, src, buf_size);
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s->extra_sample_count = buf_size;
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}
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*got_frame_ptr = 1;
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return avpkt->size;
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}
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AVCodec ff_pcm_dvd_decoder = {
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.name = "pcm_dvd",
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.long_name = NULL_IF_CONFIG_SMALL("PCM signed 16|20|24-bit big-endian for DVD media"),
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.type = AVMEDIA_TYPE_AUDIO,
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.id = AV_CODEC_ID_PCM_DVD,
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.priv_data_size = sizeof(PCMDVDContext),
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.init = pcm_dvd_decode_init,
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.decode = pcm_dvd_decode_frame,
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.close = pcm_dvd_decode_uninit,
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.capabilities = AV_CODEC_CAP_DR1,
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.sample_fmts = (const enum AVSampleFormat[]) {
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AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_NONE
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}
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};
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