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* LPCM codecs for PCM formats found in MPEG streams
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* Copyright (c) 2009 Christian Schmidt
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* This file is part of FFmpeg.
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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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* 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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* 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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* PCM codecs for encodings found in MPEG streams (DVD/Blu-ray)
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#include "libavutil/channel_layout.h"
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#include "bytestream.h"
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* Channel Mapping according to
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* Blu-ray Disc Read-Only Format Version 1
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* Part 3: Audio Visual Basic Specifications
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* 3/2+lfe L R C LS RS lfe
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* 3/4 L R C LS Rls Rrs RS X
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* 3/4+lfe L R C LS Rls Rrs RS lfe
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* Parse the header of a LPCM frame read from a MPEG-TS stream
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* @param avctx the codec context
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* @param header pointer to the first four bytes of the data packet
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static int pcm_bluray_parse_header(AVCodecContext *avctx,
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const uint8_t *header)
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static const uint8_t bits_per_samples[4] = { 0, 16, 20, 24 };
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static const uint32_t channel_layouts[16] = {
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0, AV_CH_LAYOUT_MONO, 0, AV_CH_LAYOUT_STEREO, AV_CH_LAYOUT_SURROUND,
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AV_CH_LAYOUT_2_1, AV_CH_LAYOUT_4POINT0, AV_CH_LAYOUT_2_2, AV_CH_LAYOUT_5POINT0,
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AV_CH_LAYOUT_5POINT1, AV_CH_LAYOUT_7POINT0, AV_CH_LAYOUT_7POINT1, 0, 0, 0, 0
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static const uint8_t channels[16] = {
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0, 1, 0, 2, 3, 3, 4, 4, 5, 6, 7, 8, 0, 0, 0, 0
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uint8_t channel_layout = header[2] >> 4;
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if (avctx->debug & FF_DEBUG_PICT_INFO)
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av_dlog(avctx, "pcm_bluray_parse_header: header = %02x%02x%02x%02x\n",
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header[0], header[1], header[2], header[3]);
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/* get the sample depth and derive the sample format from it */
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avctx->bits_per_coded_sample = bits_per_samples[header[3] >> 6];
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if (!(avctx->bits_per_coded_sample == 16 || avctx->bits_per_coded_sample == 24)) {
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av_log(avctx, AV_LOG_ERROR, "unsupported sample depth (%d)\n", avctx->bits_per_coded_sample);
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avctx->sample_fmt = avctx->bits_per_coded_sample == 16 ? AV_SAMPLE_FMT_S16 :
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if (avctx->sample_fmt == 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. Not all values are used. */
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switch (header[2] & 0x0f) {
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avctx->sample_rate = 48000;
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avctx->sample_rate = 96000;
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avctx->sample_rate = 192000;
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avctx->sample_rate = 0;
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av_log(avctx, AV_LOG_ERROR, "reserved sample rate (%d)\n",
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* get the channel number (and mapping). Not all values are used.
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* It must be noted that the number of channels in the MPEG stream can
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* differ from the actual meaningful number, e.g. mono audio still has two
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* channels, one being empty.
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avctx->channel_layout = channel_layouts[channel_layout];
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avctx->channels = channels[channel_layout];
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if (!avctx->channels) {
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av_log(avctx, AV_LOG_ERROR, "reserved channel configuration (%d)\n",
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avctx->bit_rate = FFALIGN(avctx->channels, 2) * avctx->sample_rate *
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avctx->bits_per_coded_sample;
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if (avctx->debug & FF_DEBUG_PICT_INFO)
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"pcm_bluray_parse_header: %d channels, %d bits per sample, %d Hz, %d 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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static int pcm_bluray_decode_frame(AVCodecContext *avctx, void *data,
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int *got_frame_ptr, AVPacket *avpkt)
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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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int num_source_channels, channel, retval;
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int sample_size, samples;
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av_log(avctx, AV_LOG_ERROR, "PCM packet too small\n");
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if (pcm_bluray_parse_header(avctx, src))
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bytestream2_init(&gb, src, buf_size);
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/* There's always an even number of channels in the source */
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num_source_channels = FFALIGN(avctx->channels, 2);
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sample_size = (num_source_channels * (avctx->sample_fmt == AV_SAMPLE_FMT_S16 ? 16 : 24)) >> 3;
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samples = buf_size / sample_size;
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/* get output buffer */
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frame->nb_samples = samples;
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if ((retval = ff_get_buffer(avctx, frame, 0)) < 0)
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dst16 = (int16_t *)frame->data[0];
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dst32 = (int32_t *)frame->data[0];
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switch (avctx->channel_layout) {
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/* cases with same number of source and coded channels */
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case AV_CH_LAYOUT_STEREO:
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case AV_CH_LAYOUT_4POINT0:
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case AV_CH_LAYOUT_2_2:
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samples *= num_source_channels;
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if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
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bytestream2_get_buffer(&gb, dst16, buf_size);
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*dst16++ = bytestream2_get_be16u(&gb);
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*dst32++ = bytestream2_get_be24u(&gb) << 8;
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/* cases where number of source channels = coded channels + 1 */
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case AV_CH_LAYOUT_MONO:
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case AV_CH_LAYOUT_SURROUND:
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case AV_CH_LAYOUT_2_1:
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case AV_CH_LAYOUT_5POINT0:
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if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
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bytestream2_get_buffer(&gb, dst16, avctx->channels * 2);
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dst16 += avctx->channels;
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channel = avctx->channels;
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*dst16++ = bytestream2_get_be16u(&gb);
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bytestream2_skip(&gb, 2);
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channel = avctx->channels;
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*dst32++ = bytestream2_get_be24u(&gb) << 8;
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bytestream2_skip(&gb, 3);
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/* remapping: L, R, C, LBack, RBack, LF */
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case AV_CH_LAYOUT_5POINT1:
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if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
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dst16[0] = bytestream2_get_be16u(&gb);
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dst16[1] = bytestream2_get_be16u(&gb);
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dst16[2] = bytestream2_get_be16u(&gb);
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dst16[4] = bytestream2_get_be16u(&gb);
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dst16[5] = bytestream2_get_be16u(&gb);
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dst16[3] = bytestream2_get_be16u(&gb);
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dst32[0] = bytestream2_get_be24u(&gb) << 8;
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dst32[1] = bytestream2_get_be24u(&gb) << 8;
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dst32[2] = bytestream2_get_be24u(&gb) << 8;
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dst32[4] = bytestream2_get_be24u(&gb) << 8;
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dst32[5] = bytestream2_get_be24u(&gb) << 8;
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dst32[3] = bytestream2_get_be24u(&gb) << 8;
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/* remapping: L, R, C, LSide, LBack, RBack, RSide, <unused> */
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case AV_CH_LAYOUT_7POINT0:
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if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
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dst16[0] = bytestream2_get_be16u(&gb);
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dst16[1] = bytestream2_get_be16u(&gb);
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dst16[2] = bytestream2_get_be16u(&gb);
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dst16[5] = bytestream2_get_be16u(&gb);
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dst16[3] = bytestream2_get_be16u(&gb);
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dst16[4] = bytestream2_get_be16u(&gb);
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dst16[6] = bytestream2_get_be16u(&gb);
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bytestream2_skip(&gb, 2);
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dst32[0] = bytestream2_get_be24u(&gb) << 8;
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dst32[1] = bytestream2_get_be24u(&gb) << 8;
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dst32[2] = bytestream2_get_be24u(&gb) << 8;
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dst32[5] = bytestream2_get_be24u(&gb) << 8;
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dst32[3] = bytestream2_get_be24u(&gb) << 8;
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dst32[4] = bytestream2_get_be24u(&gb) << 8;
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dst32[6] = bytestream2_get_be24u(&gb) << 8;
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bytestream2_skip(&gb, 3);
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/* remapping: L, R, C, LSide, LBack, RBack, RSide, LF */
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case AV_CH_LAYOUT_7POINT1:
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if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
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dst16[0] = bytestream2_get_be16u(&gb);
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dst16[1] = bytestream2_get_be16u(&gb);
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dst16[2] = bytestream2_get_be16u(&gb);
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dst16[6] = bytestream2_get_be16u(&gb);
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dst16[4] = bytestream2_get_be16u(&gb);
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dst16[5] = bytestream2_get_be16u(&gb);
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dst16[7] = bytestream2_get_be16u(&gb);
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dst16[3] = bytestream2_get_be16u(&gb);
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dst32[0] = bytestream2_get_be24u(&gb) << 8;
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dst32[1] = bytestream2_get_be24u(&gb) << 8;
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dst32[2] = bytestream2_get_be24u(&gb) << 8;
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dst32[6] = bytestream2_get_be24u(&gb) << 8;
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dst32[4] = bytestream2_get_be24u(&gb) << 8;
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dst32[5] = bytestream2_get_be24u(&gb) << 8;
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dst32[7] = bytestream2_get_be24u(&gb) << 8;
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dst32[3] = bytestream2_get_be24u(&gb) << 8;
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retval = bytestream2_tell(&gb);
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if (avctx->debug & FF_DEBUG_BITSTREAM)
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av_dlog(avctx, "pcm_bluray_decode_frame: decoded %d -> %d bytes\n",
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AVCodec ff_pcm_bluray_decoder = {
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.name = "pcm_bluray",
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.type = AVMEDIA_TYPE_AUDIO,
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.id = AV_CODEC_ID_PCM_BLURAY,
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.decode = pcm_bluray_decode_frame,
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.capabilities = 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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.long_name = NULL_IF_CONFIG_SMALL("PCM signed 16|20|24-bit big-endian for Blu-ray media"),