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https://github.com/FFmpeg/FFmpeg.git
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qpeg: Use bytestream2 functions to prevent buffer overreads.
Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>
This commit is contained in:
Aneesh Dogra
Ronald S. Bultje
parent
dccb2cd3f9
commit
3e9cd8b4b0
@ -25,16 +25,18 @@
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*/
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#include "avcodec.h"
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#include "bytestream.h"
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typedef struct QpegContext{
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AVCodecContext *avctx;
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AVFrame pic;
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uint8_t *refdata;
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uint32_t pal[256];
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GetByteContext buffer;
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} QpegContext;
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static void qpeg_decode_intra(const uint8_t *src, uint8_t *dst, int size,
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int stride, int width, int height)
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static void qpeg_decode_intra(QpegContext *qctx, uint8_t *dst,
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int stride, int width, int height)
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{
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int i;
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int code;
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@ -47,31 +49,26 @@ static void qpeg_decode_intra(const uint8_t *src, uint8_t *dst, int size,
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height--;
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dst = dst + height * stride;
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while((size > 0) && (rows_to_go > 0)) {
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code = *src++;
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size--;
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while ((bytestream2_get_bytes_left(&qctx->buffer) > 0) && (rows_to_go > 0)) {
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code = bytestream2_get_byte(&qctx->buffer);
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run = copy = 0;
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if(code == 0xFC) /* end-of-picture code */
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break;
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if(code >= 0xF8) { /* very long run */
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c0 = *src++;
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c1 = *src++;
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size -= 2;
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c0 = bytestream2_get_byte(&qctx->buffer);
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c1 = bytestream2_get_byte(&qctx->buffer);
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run = ((code & 0x7) << 16) + (c0 << 8) + c1 + 2;
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} else if (code >= 0xF0) { /* long run */
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c0 = *src++;
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size--;
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c0 = bytestream2_get_byte(&qctx->buffer);
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run = ((code & 0xF) << 8) + c0 + 2;
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} else if (code >= 0xE0) { /* short run */
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run = (code & 0x1F) + 2;
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} else if (code >= 0xC0) { /* very long copy */
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c0 = *src++;
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c1 = *src++;
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size -= 2;
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c0 = bytestream2_get_byte(&qctx->buffer);
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c1 = bytestream2_get_byte(&qctx->buffer);
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copy = ((code & 0x3F) << 16) + (c0 << 8) + c1 + 1;
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} else if (code >= 0x80) { /* long copy */
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c0 = *src++;
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size--;
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c0 = bytestream2_get_byte(&qctx->buffer);
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copy = ((code & 0x7F) << 8) + c0 + 1;
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} else { /* short copy */
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copy = code + 1;
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@ -81,8 +78,7 @@ static void qpeg_decode_intra(const uint8_t *src, uint8_t *dst, int size,
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if(run) {
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int p;
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p = *src++;
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size--;
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p = bytestream2_get_byte(&qctx->buffer);
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for(i = 0; i < run; i++) {
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dst[filled++] = p;
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if (filled >= width) {
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@ -94,9 +90,8 @@ static void qpeg_decode_intra(const uint8_t *src, uint8_t *dst, int size,
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}
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}
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} else {
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size -= copy;
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for(i = 0; i < copy; i++) {
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dst[filled++] = *src++;
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dst[filled++] = bytestream2_get_byte(&qctx->buffer);
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if (filled >= width) {
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filled = 0;
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dst -= stride;
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@ -115,9 +110,10 @@ static const int qpeg_table_w[16] =
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{ 0x00, 0x20, 0x18, 0x08, 0x18, 0x10, 0x20, 0x10, 0x08, 0x10, 0x20, 0x20, 0x08, 0x10, 0x18, 0x04};
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/* Decodes delta frames */
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static void qpeg_decode_inter(const uint8_t *src, uint8_t *dst, int size,
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int stride, int width, int height,
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int delta, const uint8_t *ctable, uint8_t *refdata)
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static void qpeg_decode_inter(QpegContext *qctx, uint8_t *dst,
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int stride, int width, int height,
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int delta, const uint8_t *ctable,
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uint8_t *refdata)
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{
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int i, j;
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int code;
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@ -132,9 +128,8 @@ static void qpeg_decode_inter(const uint8_t *src, uint8_t *dst, int size,
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height--;
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dst = dst + height * stride;
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while((size > 0) && (height >= 0)) {
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code = *src++;
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size--;
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while ((bytestream2_get_bytes_left(&qctx->buffer) > 0) && (height >= 0)) {
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code = bytestream2_get_byte(&qctx->buffer);
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if(delta) {
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/* motion compensation */
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@ -151,8 +146,7 @@ static void qpeg_decode_inter(const uint8_t *src, uint8_t *dst, int size,
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me_h = qpeg_table_h[me_idx];
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/* extract motion vector */
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corr = *src++;
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size--;
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corr = bytestream2_get_byte(&qctx->buffer);
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val = corr >> 4;
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if(val > 7)
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@ -179,8 +173,7 @@ static void qpeg_decode_inter(const uint8_t *src, uint8_t *dst, int size,
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}
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}
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}
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code = *src++;
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size--;
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code = bytestream2_get_byte(&qctx->buffer);
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}
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}
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@ -190,8 +183,7 @@ static void qpeg_decode_inter(const uint8_t *src, uint8_t *dst, int size,
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int p;
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code &= 0x1F;
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p = *src++;
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size--;
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p = bytestream2_get_byte(&qctx->buffer);
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for(i = 0; i <= code; i++) {
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dst[filled++] = p;
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if(filled >= width) {
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@ -204,14 +196,13 @@ static void qpeg_decode_inter(const uint8_t *src, uint8_t *dst, int size,
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code &= 0x1F;
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for(i = 0; i <= code; i++) {
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dst[filled++] = *src++;
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dst[filled++] = bytestream2_get_byte(&qctx->buffer);
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if(filled >= width) {
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filled = 0;
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dst -= stride;
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height--;
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}
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}
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size -= code + 1;
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} else if(code >= 0x80) { /* skip code: 0x80..0xBF */
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int skip;
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@ -219,9 +210,9 @@ static void qpeg_decode_inter(const uint8_t *src, uint8_t *dst, int size,
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/* codes 0x80 and 0x81 are actually escape codes,
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skip value minus constant is in the next byte */
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if(!code)
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skip = (*src++) + 64;
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skip = bytestream2_get_byte(&qctx->buffer) + 64;
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else if(code == 1)
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skip = (*src++) + 320;
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skip = bytestream2_get_byte(&qctx->buffer) + 320;
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else
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skip = code;
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filled += skip;
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@ -234,8 +225,9 @@ static void qpeg_decode_inter(const uint8_t *src, uint8_t *dst, int size,
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}
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} else {
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/* zero code treated as one-pixel skip */
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if(code)
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if(code) {
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dst[filled++] = ctable[code & 0x7F];
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}
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else
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filled++;
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if(filled >= width) {
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@ -251,25 +243,34 @@ static int decode_frame(AVCodecContext *avctx,
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void *data, int *data_size,
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AVPacket *avpkt)
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{
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const uint8_t *buf = avpkt->data;
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int buf_size = avpkt->size;
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uint8_t ctable[128];
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QpegContext * const a = avctx->priv_data;
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AVFrame * const p = &a->pic;
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uint8_t* outdata;
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int delta;
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const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
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if (avpkt->size < 0x86) {
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av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
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return AVERROR_INVALIDDATA;
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}
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bytestream2_init(&a->buffer, avpkt->data, avpkt->size);
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p->reference = 3;
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if (avctx->reget_buffer(avctx, p) < 0) {
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av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
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return -1;
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}
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outdata = a->pic.data[0];
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if(buf[0x85] == 0x10) {
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qpeg_decode_intra(buf+0x86, outdata, buf_size - 0x86, a->pic.linesize[0], avctx->width, avctx->height);
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bytestream2_skip(&a->buffer, 4);
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bytestream2_get_buffer(&a->buffer, ctable, 128);
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bytestream2_skip(&a->buffer, 1);
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delta = bytestream2_get_byte(&a->buffer);
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if(delta == 0x10) {
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qpeg_decode_intra(a, outdata, a->pic.linesize[0], avctx->width, avctx->height);
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} else {
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delta = buf[0x85];
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qpeg_decode_inter(buf+0x86, outdata, buf_size - 0x86, a->pic.linesize[0], avctx->width, avctx->height, delta, buf + 4, a->refdata);
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qpeg_decode_inter(a, outdata, a->pic.linesize[0], avctx->width, avctx->height, delta, ctable, a->refdata);
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}
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/* make the palette available on the way out */
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@ -282,7 +283,7 @@ static int decode_frame(AVCodecContext *avctx,
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*data_size = sizeof(AVFrame);
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*(AVFrame*)data = a->pic;
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return buf_size;
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return avpkt->size;
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}
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static av_cold int decode_init(AVCodecContext *avctx){
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