diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/demuxers/demux_idcin.c | 115 |
1 files changed, 108 insertions, 7 deletions
diff --git a/src/demuxers/demux_idcin.c b/src/demuxers/demux_idcin.c index 353c1f009..cc8206de1 100644 --- a/src/demuxers/demux_idcin.c +++ b/src/demuxers/demux_idcin.c @@ -21,7 +21,49 @@ * For more information regarding the Id CIN file format, visit: * http://www.csse.monash.edu.au/~timf/ * - * $Id: demux_idcin.c,v 1.4 2002/08/12 00:13:32 tmmm Exp $ + * CIN is a somewhat quirky and ill-defined format. Here are some notes + * for anyone trying to understand the technical details of this format: + * + * The format has no definite file signature. This is problematic for a + * general-purpose media player that wants to automatically detect file + * types. However, a CIN file does start with 5 32-bit numbers that + * specify audio and video parameters. This demuxer gets around the lack + * of file signature by performing sanity checks on those parameters. + * Probabalistically, this is a reasonable solution since the number of + * valid combinations of the 5 parameters is a very small subset of the + * total 160-bit number space. + * + * Refer to the function demux_idcin_open() for the precise A/V parameters + * that this demuxer allows. + * + * Next, each audio and video frame has a duration of 1/14 sec. If the + * audio sample rate is a multiple of the common frequency 22050 Hz it will + * divide evenly by 14. However, if the sample rate is 11025 Hz: + * 11025 (samples/sec) / 14 (frames/sec) = 787.5 (samples/frame) + * The way the CIN stores audio in this case is by storing 787 sample + * frames in the first audio frame and 788 sample frames in the second + * audio frame. Therefore, the total number of bytes in an audio frame + * is given as: + * audio frame #0: 787 * (bytes/sample) * (# channels) bytes in frame + * audio frame #1: 788 * (bytes/sample) * (# channels) bytes in frame + * audio frame #2: 787 * (bytes/sample) * (# channels) bytes in frame + * audio frame #3: 788 * (bytes/sample) * (# channels) bytes in frame + * + * Finally, not all Id CIN creation tools agree on the resolution of the + * color palette, apparently. Some creation tools specify red, green, and + * blue palette components in terms of 6-bit VGA color DAC values which + * range from 0..63. Other tools specify the RGB components as full 8-bit + * values that range from 0..63. Since there are no markers in the file to + * differentiate between the two variants, this demuxer uses the following + * heuristic: + * - load the 768 palette bytes from disk + * - assume that they will need to be shifted left by 2 bits to + * transform them from 6-bit values to 8-bit values + * - scan through all 768 palette bytes + * - if any bytes exceed 63, do not shift the bytes at all before + * transmitting them to the video decoder + * + * $Id: demux_idcin.c,v 1.5 2002/09/01 06:43:26 tmmm Exp $ */ #ifdef HAVE_CONFIG_H @@ -78,6 +120,9 @@ typedef struct { unsigned int audio_bytes_per_sample; unsigned int audio_channels; + int audio_chunk_size1; + int audio_chunk_size2; + unsigned char huffman_table[HUFFMAN_TABLE_SIZE]; } demux_idcin_t; @@ -94,6 +139,8 @@ static void *demux_idcin_loop (void *this_gen) { int i; unsigned int remaining_sample_bytes; uint64_t pts_counter = 0; + int current_audio_chunk = 1; + int scale_bits; pthread_mutex_lock( &this->mutex ); @@ -132,13 +179,22 @@ static void *demux_idcin_loop (void *this_gen) { break; } + /* scan the palette to figure out if it's 6- or 8-bit; + * assume 6-bit palette until a value > 63 is seen */ + scale_bits = 2; + for (i = 0; i < PALETTE_SIZE * 3; i++) + if (disk_palette[i] > 63) { + scale_bits = 0; + break; + } + /* convert palette to internal structure */ for (i = 0; i < PALETTE_SIZE; i++) { /* these are VGA color DAC values, which means they only range * from 0..63; adjust as appropriate */ - palette[i].r = disk_palette[i * 3 + 0] * 4; - palette[i].g = disk_palette[i * 3 + 1] * 4; - palette[i].b = disk_palette[i * 3 + 2] * 4; + palette[i].r = disk_palette[i * 3 + 0] << scale_bits; + palette[i].g = disk_palette[i * 3 + 1] << scale_bits; + palette[i].b = disk_palette[i * 3 + 2] << scale_bits; } buf = this->video_fifo->buffer_pool_alloc (this->video_fifo); @@ -159,9 +215,6 @@ static void *demux_idcin_loop (void *this_gen) { break; } remaining_sample_bytes = LE_32(&preamble[0]) - 4; -//printf (" loading video frame at offset %llX, %X bytes\n", -// this->input->get_current_pos(this->input), -// remaining_sample_bytes); while (remaining_sample_bytes) { buf = this->video_fifo->buffer_pool_alloc (this->video_fifo); @@ -194,6 +247,41 @@ static void *demux_idcin_loop (void *this_gen) { /* load the audio frame */ if (this->audio_fifo && this->audio_sample_rate) { + + if (current_audio_chunk == 1) { + remaining_sample_bytes = this->audio_chunk_size1; + current_audio_chunk = 2; + } else { + remaining_sample_bytes = this->audio_chunk_size2; + current_audio_chunk = 1; + } + + while (remaining_sample_bytes) { + buf = this->audio_fifo->buffer_pool_alloc (this->audio_fifo); + buf->type = BUF_AUDIO_LPCM_LE; + buf->input_pos = this->input->get_current_pos(this->input); + buf->input_length = this->filesize; + buf->input_time = pts_counter / 90000; + buf->pts = pts_counter; + + if (remaining_sample_bytes > buf->max_size) + buf->size = buf->max_size; + else + buf->size = remaining_sample_bytes; + remaining_sample_bytes -= buf->size; + + if (this->input->read(this->input, buf->content, buf->size) != + buf->size) { + buf->free_buffer(buf); + this->status = DEMUX_FINISHED; + break; + } + + if (!remaining_sample_bytes) + buf->decoder_flags |= BUF_FLAG_FRAME_END; + + this->audio_fifo->put(this->audio_fifo, buf); + } } pts_counter += IDCIN_FRAME_PTS_INC; @@ -401,6 +489,19 @@ static int demux_idcin_start (demux_plugin_t *this_gen, this->video_fifo->put (this->video_fifo, buf); if (this->audio_fifo && this->audio_channels) { + + /* initialize the chunk sizes */ + if (this->audio_sample_rate % 14 != 0) { + this->audio_chunk_size1 = (this->audio_sample_rate / 14) * + this->audio_bytes_per_sample * this->audio_channels; + this->audio_chunk_size2 = (this->audio_sample_rate / 14 + 1) * + this->audio_bytes_per_sample * this->audio_channels; + } else { + this->audio_chunk_size1 = this->audio_chunk_size2 = + (this->audio_sample_rate / 14) * this->audio_bytes_per_sample * + this->audio_channels; + } + buf = this->audio_fifo->buffer_pool_alloc (this->audio_fifo); buf->type = BUF_AUDIO_LPCM_LE; buf->decoder_flags = BUF_FLAG_HEADER; |