static int smacker_read_packet(AVFormatContext *s, AVPacket *pkt) { SmackerContext *smk = s->priv_data; int flags; int ret; int i; int frame_size = 0; int palchange = 0; if (s->pb->eof_reached || smk->cur_frame >= smk->frames) return AVERROR_EOF; /* if we demuxed all streams, pass another frame */ if(smk->curstream < 0) { avio_seek(s->pb, smk->nextpos, 0); frame_size = smk->frm_size[smk->cur_frame] & (~3); flags = smk->frm_flags[smk->cur_frame]; /* handle palette change event */ if(flags & SMACKER_PAL){ int size, sz, t, off, j, pos; uint8_t *pal = smk->pal; uint8_t oldpal[768]; memcpy(oldpal, pal, 768); size = avio_r8(s->pb); size = size * 4 - 1; frame_size -= size; frame_size--; sz = 0; pos = avio_tell(s->pb) + size; while(sz < 256){ t = avio_r8(s->pb); if(t & 0x80){ /* skip palette entries */ sz += (t & 0x7F) + 1; pal += ((t & 0x7F) + 1) * 3; } else if(t & 0x40){ /* copy with offset */ off = avio_r8(s->pb); j = (t & 0x3F) + 1; if (off + j > 0x100) { av_log(s, AV_LOG_ERROR, "Invalid palette update, offset=%d length=%d extends beyond palette size\n", off, j); return AVERROR_INVALIDDATA; } off *= 3; while(j-- && sz < 256) { *pal++ = oldpal[off + 0]; *pal++ = oldpal[off + 1]; *pal++ = oldpal[off + 2]; sz++; off += 3; } } else { /* new entries */ *pal++ = smk_pal[t]; *pal++ = smk_pal[avio_r8(s->pb) & 0x3F]; *pal++ = smk_pal[avio_r8(s->pb) & 0x3F]; sz++; } } avio_seek(s->pb, pos, 0); palchange |= 1; } flags >>= 1; smk->curstream = -1; /* if audio chunks are present, put them to stack and retrieve later */ for(i = 0; i < 7; i++) { if(flags & 1) { int size; uint8_t *tmpbuf; size = avio_rl32(s->pb) - 4; frame_size -= size; frame_size -= 4; smk->curstream++; tmpbuf = av_realloc(smk->bufs[smk->curstream], size); if (!tmpbuf) return AVERROR(ENOMEM); smk->bufs[smk->curstream] = tmpbuf; smk->buf_sizes[smk->curstream] = size; ret = avio_read(s->pb, smk->bufs[smk->curstream], size); if(ret != size) return AVERROR(EIO); smk->stream_id[smk->curstream] = smk->indexes[i]; } flags >>= 1; } if (frame_size < 0) return AVERROR_INVALIDDATA; if (av_new_packet(pkt, frame_size + 769)) return AVERROR(ENOMEM); if(smk->frm_size[smk->cur_frame] & 1) palchange |= 2; pkt->data[0] = palchange; memcpy(pkt->data + 1, smk->pal, 768); ret = avio_read(s->pb, pkt->data + 769, frame_size); if(ret != frame_size) return AVERROR(EIO); pkt->stream_index = smk->videoindex; pkt->pts = smk->cur_frame; pkt->size = ret + 769; smk->cur_frame++; smk->nextpos = avio_tell(s->pb); } else { if (av_new_packet(pkt, smk->buf_sizes[smk->curstream])) return AVERROR(ENOMEM); memcpy(pkt->data, smk->bufs[smk->curstream], smk->buf_sizes[smk->curstream]); pkt->size = smk->buf_sizes[smk->curstream]; pkt->stream_index = smk->stream_id[smk->curstream]; pkt->pts = smk->aud_pts[smk->curstream]; smk->aud_pts[smk->curstream] += AV_RL32(pkt->data); smk->curstream--; } return 0; }