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- /*
- * Some mp3 related code for Sega/Mega CD.
- * Uses Libav/FFmpeg libavcodec
- * (C) notaz, 2013
- *
- * This work is licensed under the terms of MAME license.
- * See COPYING file in the top-level directory.
- */
- #include <stdio.h>
- #include <string.h>
- #include <libavcodec/avcodec.h>
- #include <dlfcn.h>
- #include <pico/pico_int.h>
- #include "../libpicofe/lprintf.h"
- #include "mp3.h"
- static AVCodecContext *ctx;
- /* avoid compile time linking to libavcodec due to huge list of it's deps..
- * we also use this old API as newer one is not available on pandora */
- void (*p_av_init_packet)(AVPacket *pkt);
- int (*p_avcodec_decode_audio3)(AVCodecContext *avctx, int16_t *samples,
- int *frame_size_ptr, AVPacket *avpkt);
- int mp3dec_decode(FILE *f, int *file_pos, int file_len)
- {
- unsigned char input_buf[2 * 1024];
- int frame_size;
- AVPacket avpkt;
- int bytes_in;
- int bytes_out;
- int offset;
- int len;
- p_av_init_packet(&avpkt);
- do
- {
- if (*file_pos >= file_len)
- return 1; // EOF, nothing to do
- fseek(f, *file_pos, SEEK_SET);
- bytes_in = fread(input_buf, 1, sizeof(input_buf), f);
- offset = mp3_find_sync_word(input_buf, bytes_in);
- if (offset < 0) {
- lprintf("find_sync_word (%i/%i) err %i\n",
- *file_pos, file_len, offset);
- *file_pos = file_len;
- return 1; // EOF
- }
- // to avoid being flooded with "incorrect frame size" errors,
- // we must calculate and pass exact frame size - lame
- frame_size = mpeg1_l3_bitrates[input_buf[offset + 2] >> 4];
- frame_size = frame_size * 144000 / 44100;
- frame_size += (input_buf[offset + 2] >> 1) & 1;
- if (offset > 0 && bytes_in - offset < frame_size) {
- // underflow
- *file_pos += offset;
- continue;
- }
- avpkt.data = input_buf + offset;
- avpkt.size = frame_size;
- bytes_out = sizeof(cdda_out_buffer);
- #if LIBAVCODEC_VERSION_MAJOR < 53
- // stupidity in v52: enforces this size even when
- // it doesn't need/use that much at all
- bytes_out = AVCODEC_MAX_AUDIO_FRAME_SIZE;
- #endif
- len = p_avcodec_decode_audio3(ctx, cdda_out_buffer,
- &bytes_out, &avpkt);
- if (len <= 0) {
- lprintf("mp3 decode err (%i/%i) %i\n",
- *file_pos, file_len, len);
- // attempt to skip the offending frame..
- *file_pos += offset + 1;
- continue;
- }
- *file_pos += offset + len;
- }
- while (0);
- return 0;
- }
- int mp3dec_start(FILE *f, int fpos_start)
- {
- void (*avcodec_register_all)(void);
- AVCodec *(*avcodec_find_decoder)(enum CodecID id);
- AVCodecContext *(*avcodec_alloc_context)(void);
- int (*avcodec_open)(AVCodecContext *avctx, AVCodec *codec);
- void (*av_free)(void *ptr);
- AVCodec *codec;
- void *soh;
- int ret;
- if (ctx != NULL)
- return 0;
- // either v52 or v53 should be ok
- soh = dlopen("libavcodec.so.52", RTLD_NOW);
- if (soh == NULL)
- soh = dlopen("libavcodec.so.53", RTLD_NOW);
- if (soh == NULL) {
- lprintf("mp3dec: load libavcodec.so: %s\n", dlerror());
- return -1;
- }
- avcodec_register_all = dlsym(soh, "avcodec_register_all");
- avcodec_find_decoder = dlsym(soh, "avcodec_find_decoder");
- avcodec_alloc_context = dlsym(soh, "avcodec_alloc_context");
- avcodec_open = dlsym(soh, "avcodec_open");
- av_free = dlsym(soh, "av_free");
- p_av_init_packet = dlsym(soh, "av_init_packet");
- p_avcodec_decode_audio3 = dlsym(soh, "avcodec_decode_audio3");
- if (avcodec_register_all == NULL || avcodec_find_decoder == NULL
- || avcodec_alloc_context == NULL || avcodec_open == NULL
- || av_free == NULL
- || p_av_init_packet == NULL || p_avcodec_decode_audio3 == NULL)
- {
- lprintf("mp3dec: missing symbol(s) in libavcodec.so\n");
- dlclose(soh);
- return -1;
- }
- // init decoder
- //avcodec_init();
- avcodec_register_all();
- // AV_CODEC_ID_MP3 ?
- codec = avcodec_find_decoder(CODEC_ID_MP3);
- if (codec == NULL) {
- lprintf("mp3dec: codec missing\n");
- return -1;
- }
- ctx = avcodec_alloc_context();
- if (ctx == NULL) {
- lprintf("mp3dec: avcodec_alloc_context failed\n");
- return -1;
- }
- ret = avcodec_open(ctx, codec);
- if (ret < 0) {
- lprintf("mp3dec: avcodec_open failed: %d\n", ret);
- av_free(ctx);
- ctx = NULL;
- return -1;
- }
- return 0;
- }
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