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aacdec: refactor the actual aac decoding code into its own function

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aac_decode_frame() remains as AVPacket handling a wrapper. The actual
decoding function takes a GetBitContext as input and will be used be the
AAC LATM decoder to avoid copying the unaligned AAC bitstream.

Originally committed as revision 25640 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Janne Grunau 2010-11-02 08:29:43 +00:00
parent be63b4ba22
commit 66a71d989f
1 changed files with 34 additions and 23 deletions
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57
libavcodec/aacdec.c
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@ -1921,24 +1921,17 @@ static int parse_adts_frame_header(AACContext *ac, GetBitContext *gb)
return size;
}
static int aac_decode_frame(AVCodecContext *avctx, void *data,
int *data_size, AVPacket *avpkt)
static int aac_decode_frame_int(AVCodecContext *avctx, void *data,
int *data_size, GetBitContext *gb)
{
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
AACContext *ac = avctx->priv_data;
ChannelElement *che = NULL, *che_prev = NULL;
GetBitContext gb;
enum RawDataBlockType elem_type, elem_type_prev = TYPE_END;
int err, elem_id, data_size_tmp;
int buf_consumed;
int samples = 0, multiplier;
int buf_offset;
init_get_bits(&gb, buf, buf_size * 8);
if (show_bits(&gb, 12) == 0xfff) {
if (parse_adts_frame_header(ac, &gb) < 0) {
if (show_bits(gb, 12) == 0xfff) {
if (parse_adts_frame_header(ac, gb) < 0) {
av_log(avctx, AV_LOG_ERROR, "Error decoding AAC frame header.\n");
return -1;
}
@ -1950,8 +1943,8 @@ static int aac_decode_frame(AVCodecContext *avctx, void *data,
ac->tags_mapped = 0;
// parse
while ((elem_type = get_bits(&gb, 3)) != TYPE_END) {
elem_id = get_bits(&gb, 4);
while ((elem_type = get_bits(gb, 3)) != TYPE_END) {
elem_id = get_bits(gb, 4);
if (elem_type < TYPE_DSE) {
if (!(che=get_che(ac, elem_type, elem_id))) {
@ -1965,29 +1958,29 @@ static int aac_decode_frame(AVCodecContext *avctx, void *data,
switch (elem_type) {
case TYPE_SCE:
err = decode_ics(ac, &che->ch[0], &gb, 0, 0);
err = decode_ics(ac, &che->ch[0], gb, 0, 0);
break;
case TYPE_CPE:
err = decode_cpe(ac, &gb, che);
err = decode_cpe(ac, gb, che);
break;
case TYPE_CCE:
err = decode_cce(ac, &gb, che);
err = decode_cce(ac, gb, che);
break;
case TYPE_LFE:
err = decode_ics(ac, &che->ch[0], &gb, 0, 0);
err = decode_ics(ac, &che->ch[0], gb, 0, 0);
break;
case TYPE_DSE:
err = skip_data_stream_element(ac, &gb);
err = skip_data_stream_element(ac, gb);
break;
case TYPE_PCE: {
enum ChannelPosition new_che_pos[4][MAX_ELEM_ID];
memset(new_che_pos, 0, 4 * MAX_ELEM_ID * sizeof(new_che_pos[0][0]));
if ((err = decode_pce(ac, new_che_pos, &gb)))
if ((err = decode_pce(ac, new_che_pos, gb)))
break;
if (ac->output_configured > OC_TRIAL_PCE)
av_log(avctx, AV_LOG_ERROR,
@ -1999,13 +1992,13 @@ static int aac_decode_frame(AVCodecContext *avctx, void *data,
case TYPE_FIL:
if (elem_id == 15)
elem_id += get_bits(&gb, 8) - 1;
if (get_bits_left(&gb) < 8 * elem_id) {
elem_id += get_bits(gb, 8) - 1;
if (get_bits_left(gb) < 8 * elem_id) {
av_log(avctx, AV_LOG_ERROR, overread_err);
return -1;
}
while (elem_id > 0)
elem_id -= decode_extension_payload(ac, &gb, elem_id, che_prev, elem_type_prev);
elem_id -= decode_extension_payload(ac, gb, elem_id, che_prev, elem_type_prev);
err = 0; /* FIXME */
break;
@ -2020,7 +2013,7 @@ static int aac_decode_frame(AVCodecContext *avctx, void *data,
if (err)
return err;
if (get_bits_left(&gb) < 3) {
if (get_bits_left(gb) < 3) {
av_log(avctx, AV_LOG_ERROR, overread_err);
return -1;
}
@ -2050,6 +2043,24 @@ static int aac_decode_frame(AVCodecContext *avctx, void *data,
if (ac->output_configured)
ac->output_configured = OC_LOCKED;
return 0;
}
static int aac_decode_frame(AVCodecContext *avctx, void *data,
int *data_size, AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
GetBitContext gb;
int buf_consumed;
int buf_offset;
int err;
init_get_bits(&gb, buf, buf_size * 8);
if ((err = aac_decode_frame_int(avctx, data, data_size, &gb)) < 0)
return err;
buf_consumed = (get_bits_count(&gb) + 7) >> 3;
for (buf_offset = buf_consumed; buf_offset < buf_size; buf_offset++)
if (buf[buf_offset])