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rtpdec_jpeg: Store and reuse old qtables for q values 128-254 

Signed-off-by: Martin Storsjö <martin@martin.st>
This commit is contained in:
Martin Storsjö 2012-09-11 14:29:54 +03:00
parent a252649059
commit a218deb856
1 changed files with 27 additions and 6 deletions
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33
libavformat/rtpdec_jpeg.c
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@ -32,6 +32,8 @@ struct PayloadContext {
AVIOContext *frame; ///< current frame buffer
uint32_t timestamp; ///< current frame timestamp
int hdr_size; ///< size of the current frame header
uint8_t qtables[128][128];
uint8_t qtables_len[128];
};
static const uint8_t default_quantizers[128] = {
@ -267,12 +269,6 @@ static int jpeg_parse_packet(AVFormatContext *ctx, PayloadContext *jpeg,
if (precision)
av_log(ctx, AV_LOG_WARNING, "Only 8-bit precision is supported.\n");
if (q == 255 && qtable_len == 0) {
av_log(ctx, AV_LOG_ERROR,
"Invalid RTP/JPEG packet. Quantization tables not found.\n");
return AVERROR_INVALIDDATA;
}
if (qtable_len > 0) {
if (len < qtable_len) {
av_log(ctx, AV_LOG_ERROR, "Too short RTP/JPEG packet.\n");
@ -281,6 +277,31 @@ static int jpeg_parse_packet(AVFormatContext *ctx, PayloadContext *jpeg,
qtables = buf;
buf += qtable_len;
len -= qtable_len;
if (q < 255) {
if (jpeg->qtables_len[q - 128] &&
(jpeg->qtables_len[q - 128] != qtable_len ||
memcmp(qtables, &jpeg->qtables[q - 128][0], qtable_len))) {
av_log(ctx, AV_LOG_WARNING,
"Quantization tables for q=%d changed\n", q);
} else if (!jpeg->qtables_len[q - 128] && qtable_len <= 128) {
memcpy(&jpeg->qtables[q - 128][0], qtables,
qtable_len);
jpeg->qtables_len[q - 128] = qtable_len;
}
}
} else {
if (q == 255) {
av_log(ctx, AV_LOG_ERROR,
"Invalid RTP/JPEG packet. Quantization tables not found.\n");
return AVERROR_INVALIDDATA;
}
if (!jpeg->qtables_len[q - 128]) {
av_log(ctx, AV_LOG_ERROR,
"No quantization tables known for q=%d yet.\n", q);
return AVERROR_INVALIDDATA;
}
qtables = &jpeg->qtables[q - 128][0];
qtable_len = jpeg->qtables_len[q - 128];
}
}