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libavcodec/libcelt_dec.c

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00001 /*
00002  * Xiph CELT decoder using libcelt
00003  * Copyright (c) 2011 Nicolas George
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 #include <celt/celt.h>
00023 #include <celt/celt_header.h>
00024 #include "avcodec.h"
00025 #include "libavutil/intreadwrite.h"
00026 
00027 struct libcelt_context {
00028     CELTMode *mode;
00029     CELTDecoder *dec;
00030     AVFrame frame;
00031     int discard;
00032 };
00033 
00034 static int ff_celt_error_to_averror(int err)
00035 {
00036     switch (err) {
00037         case CELT_BAD_ARG:          return AVERROR(EINVAL);
00038 #ifdef CELT_BUFFER_TOO_SMALL
00039         case CELT_BUFFER_TOO_SMALL: return AVERROR(ENOBUFS);
00040 #endif
00041         case CELT_INTERNAL_ERROR:   return AVERROR(EFAULT);
00042         case CELT_CORRUPTED_DATA:   return AVERROR_INVALIDDATA;
00043         case CELT_UNIMPLEMENTED:    return AVERROR(ENOSYS);
00044 #ifdef ENOTRECOVERABLE
00045         case CELT_INVALID_STATE:    return AVERROR(ENOTRECOVERABLE);
00046 #endif
00047         case CELT_ALLOC_FAIL:       return AVERROR(ENOMEM);
00048         default:                    return AVERROR(EINVAL);
00049     }
00050 }
00051 
00052 static int ff_celt_bitstream_version_hack(CELTMode *mode)
00053 {
00054     CELTHeader header = { .version_id = 0 };
00055     celt_header_init(&header, mode, 960, 2);
00056     return header.version_id;
00057 }
00058 
00059 static av_cold int libcelt_dec_init(AVCodecContext *c)
00060 {
00061     struct libcelt_context *celt = c->priv_data;
00062     int err;
00063 
00064     if (!c->channels || !c->frame_size ||
00065         c->frame_size > INT_MAX / sizeof(int16_t) / c->channels)
00066         return AVERROR(EINVAL);
00067     celt->mode = celt_mode_create(c->sample_rate, c->frame_size, &err);
00068     if (!celt->mode)
00069         return ff_celt_error_to_averror(err);
00070     celt->dec = celt_decoder_create_custom(celt->mode, c->channels, &err);
00071     if (!celt->dec) {
00072         celt_mode_destroy(celt->mode);
00073         return ff_celt_error_to_averror(err);
00074     }
00075     if (c->extradata_size >= 4) {
00076         celt->discard = AV_RL32(c->extradata);
00077         if (celt->discard < 0 || celt->discard >= c->frame_size) {
00078             av_log(c, AV_LOG_WARNING,
00079                    "Invalid overlap (%d), ignored.\n", celt->discard);
00080             celt->discard = 0;
00081         }
00082     }
00083     if (c->extradata_size >= 8) {
00084         unsigned version = AV_RL32(c->extradata + 4);
00085         unsigned lib_version = ff_celt_bitstream_version_hack(celt->mode);
00086         if (version != lib_version)
00087             av_log(c, AV_LOG_WARNING,
00088                    "CELT bitstream version 0x%x may be "
00089                    "improperly decoded by libcelt for version 0x%x.\n",
00090                    version, lib_version);
00091     }
00092     c->sample_fmt = AV_SAMPLE_FMT_S16;
00093     avcodec_get_frame_defaults(&celt->frame);
00094     c->coded_frame = &celt->frame;
00095     return 0;
00096 }
00097 
00098 static av_cold int libcelt_dec_close(AVCodecContext *c)
00099 {
00100     struct libcelt_context *celt = c->priv_data;
00101 
00102     celt_decoder_destroy(celt->dec);
00103     celt_mode_destroy(celt->mode);
00104     return 0;
00105 }
00106 
00107 static int libcelt_dec_decode(AVCodecContext *c, void *frame,
00108                               int *got_frame_ptr, AVPacket *pkt)
00109 {
00110     struct libcelt_context *celt = c->priv_data;
00111     int err;
00112     int16_t *pcm;
00113 
00114     celt->frame.nb_samples = c->frame_size;
00115     err = c->get_buffer(c, &celt->frame);
00116     if (err < 0) {
00117         av_log(c, AV_LOG_ERROR, "get_buffer() failed\n");
00118         return err;
00119     }
00120     pcm = (int16_t *)celt->frame.data[0];
00121     err = celt_decode(celt->dec, pkt->data, pkt->size, pcm, c->frame_size);
00122     if (err < 0)
00123         return ff_celt_error_to_averror(err);
00124     if (celt->discard) {
00125         celt->frame.nb_samples -= celt->discard;
00126         memmove(pcm, pcm + celt->discard * c->channels,
00127                 celt->frame.nb_samples * c->channels * sizeof(int16_t));
00128         celt->discard = 0;
00129     }
00130     *got_frame_ptr = 1;
00131     *(AVFrame *)frame = celt->frame;
00132     return pkt->size;
00133 }
00134 
00135 AVCodec ff_libcelt_decoder = {
00136     .name           = "libcelt",
00137     .type           = AVMEDIA_TYPE_AUDIO,
00138     .id             = CODEC_ID_CELT,
00139     .priv_data_size = sizeof(struct libcelt_context),
00140     .init           = libcelt_dec_init,
00141     .close          = libcelt_dec_close,
00142     .decode         = libcelt_dec_decode,
00143     .capabilities   = CODEC_CAP_DR1,
00144     .long_name      = NULL_IF_CONFIG_SMALL("Xiph CELT decoder using libcelt"),
00145 };
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