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ttadec: fix last frame handling when seeking 

Using a frame count, as is done currently, does not work at all with
seeking. Instead, when the number of samples in the final frame has
been decoded, we check if only the 32-bit CRC is remaining. If so, we
assume that it is the final frame.

There is no longer a need to keep total_frames in TTAContext.
This commit is contained in:
Justin Ruggles 2012-02-10 17:51:11 -05:00
parent 68a04b0cce
commit 5778299c7e
1 changed files with 17 additions and 13 deletions
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30
libavcodec/tta.c
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@ -64,7 +64,7 @@ typedef struct TTAContext {
int format, channels, bps;
unsigned data_length;
int frame_length, last_frame_length, total_frames;
int frame_length, last_frame_length;
int32_t *decode_buffer;
@ -198,6 +198,7 @@ static int tta_check_crc(TTAContext *s, const uint8_t *buf, int buf_size)
static av_cold int tta_decode_init(AVCodecContext * avctx)
{
TTAContext *s = avctx->priv_data;
int total_frames;
s->avctx = avctx;
@ -262,24 +263,24 @@ static av_cold int tta_decode_init(AVCodecContext * avctx)
s->frame_length = 256 * avctx->sample_rate / 245;
s->last_frame_length = s->data_length % s->frame_length;
s->total_frames = s->data_length / s->frame_length +
(s->last_frame_length ? 1 : 0);
total_frames = s->data_length / s->frame_length +
(s->last_frame_length ? 1 : 0);
av_log(s->avctx, AV_LOG_DEBUG, "format: %d chans: %d bps: %d rate: %d block: %d\n",
s->format, avctx->channels, avctx->bits_per_coded_sample, avctx->sample_rate,
avctx->block_align);
av_log(s->avctx, AV_LOG_DEBUG, "data_length: %d frame_length: %d last: %d total: %d\n",
s->data_length, s->frame_length, s->last_frame_length, s->total_frames);
s->data_length, s->frame_length, s->last_frame_length, total_frames);
// FIXME: seek table
if (avctx->extradata_size <= 26 || s->total_frames > INT_MAX / 4 ||
avctx->extradata_size - 26 < s->total_frames * 4)
if (avctx->extradata_size <= 26 || total_frames > INT_MAX / 4 ||
avctx->extradata_size - 26 < total_frames * 4)
av_log(avctx, AV_LOG_WARNING, "Seek table missing or too small\n");
else if (avctx->err_recognition & AV_EF_CRCCHECK) {
if (tta_check_crc(s, avctx->extradata + 22, s->total_frames * 4))
if (tta_check_crc(s, avctx->extradata + 22, total_frames * 4))
return AVERROR_INVALIDDATA;
}
skip_bits_long(&s->gb, 32 * s->total_frames);
skip_bits_long(&s->gb, 32 * total_frames);
skip_bits_long(&s->gb, 32); // CRC32 of seektable
if(s->frame_length >= UINT_MAX / (s->channels * sizeof(int32_t))){
@ -325,11 +326,6 @@ static int tta_decode_frame(AVCodecContext *avctx, void *data,
init_get_bits(&s->gb, buf, buf_size*8);
// FIXME: seeking
s->total_frames--;
if (!s->total_frames && s->last_frame_length)
framelen = s->last_frame_length;
/* get output buffer */
s->frame.nb_samples = framelen;
if ((ret = ff_get_buffer(avctx, &s->frame)) < 0) {
@ -348,6 +344,7 @@ static int tta_decode_frame(AVCodecContext *avctx, void *data,
rice_init(&s->ch_ctx[i].rice, 10, 10);
}
i = 0;
for (p = s->decode_buffer; p < s->decode_buffer + (framelen * s->channels); p++) {
int32_t *predictor = &s->ch_ctx[cur_chan].predictor;
TTAFilter *filter = &s->ch_ctx[cur_chan].filter;
@ -424,9 +421,16 @@ static int tta_decode_frame(AVCodecContext *avctx, void *data,
*r = *(r + 1) - *r;
}
cur_chan = 0;
i++;
// check for last frame
if (i == s->last_frame_length && get_bits_left(&s->gb) / 8 == 4) {
s->frame.nb_samples = framelen = s->last_frame_length;
break;
}
}
}
align_get_bits(&s->gb);
if (get_bits_left(&s->gb) < 32) {
ret = AVERROR_INVALIDDATA;
goto error;